This is based on Peter Grill's answer to your earlier question.
Note that I'm not sure quite what it is meant to look like since neither the first image you posted nor the second corresponds to the content of the MWE. Moreover, I still have absolutely zero idea what your description means, and you have not even attempted to clarify this.
EDIT: An Unholy Cross Between the MWE & the 'Brazil' Image
\documentclass[11pt,twoside,openany,svgnames,x11names,a4paper]{book}% paper added to match image used for testing
\usepackage{afterpage}
\usepackage[explicit]{titlesec}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning}
\usepackage{enumitem}
\usepackage{geometry}
\geometry{
% paperwidth=216mm, paperheight=303mm,% changed just for illustration so the background image fits the page
left=23mm,
right=18mm,
top=23mm, bottom=23mm,
headheight=\baselineskip,
headsep=7mm,
footskip=10mm,
}
\definecolor{chapopcolor}{cmyk}{.18,0,1,0}
\newcommand\chapterillustration{}
\titleformat{\chapter}{}{}{0pt}{
\thispagestyle{empty}%
\begin{tikzpicture}[overlay,remember picture]
\node [anchor=south west, chapter pic] at (current page.south west) {\includegraphics[scale=1.414,angle=90]{\chapterillustration}};
\fill[chapopcolor,opacity=1] ([yshift=15mm] current page.west) rectangle ([yshift=-30mm] current page.east);
\fill[chapopcolor,opacity=.75] ([yshift=-30mm] current page.west) rectangle (current page.south east);
\node (chapter name) [anchor=south east, chapter name] at (current page.east) {\chaptername};
\node [chapter number] {\thechapter};
\end{tikzpicture}
\afterpage{%
\clearpage
\thispagestyle{empty}%
\begin{tikzpicture}[overlay,remember picture]
\node [anchor=south east, chapter pic] at (current page.south east) {\includegraphics[scale=1.414,angle=90]{\chapterillustration}};
\fill[chapopcolor,opacity=1] ([yshift=15mm] current page.west) rectangle ([yshift=-30mm] current page.east);
\fill[chapopcolor,opacity=.75] ([yshift=-30mm] current page.west) rectangle (current page.south east);
\node (chapter text) [chapter text, anchor=south west] at ([xshift=50mm] current page.west) {#1};
\end{tikzpicture}
\vspace*{135mm}%\dimexpr.5\textheight+30mm}
\section*{}%
}%
}
\titlespacing*{\chapter}{0pt}{0pt}{135mm}
\tikzset{
chapter pic/.style={
inner sep=0pt,
outer sep=0pt,
opacity=.5
},
chapter name/.style={
xshift=-25mm,
yshift=30mm,
font=\sffamily\bfseries\Huge,
text=white},
chapter number/.style={
right=0pt of chapter name,
font=\sffamily\bfseries\Huge,
white,
scale=2.5
},
chapter text/.style={
fill=Sienna!80!black,
text=white,
font=\Huge\bfseries,
inner ysep=12pt,
inner xsep=20pt,
rounded rectangle,
xshift=-20mm,
yshift=7.5mm
},
}
\newlist{topiclist}{enumerate}{1}
\setlist[topiclist]{format=\color{blue}\sffamily\bfseries, label=\arabic*}
\newlist{curriculumlist}{enumerate}{1}
\setlist[curriculumlist]{format=\color{blue}\sffamily\bfseries, label=\thechapter\Alph*}
\newenvironment{curriculum}[1]{%
\begin{minipage}[t]{.8\linewidth}
\subsection*{\color{blue}#1}
\begin{curriculumlist}
}{%
\end{curriculumlist}
\end{minipage}
}
\newenvironment{topics}[1]{%
\begin{minipage}[t]{.8\linewidth}\raggedright
\subsection*{\color{blue}#1}
\begin{topiclist}
}{%
\end{topiclist}
\end{minipage}
}
\begin{document}
\pagestyle{headings}
\renewcommand\chapterillustration{enfys}
\chapter{Chapter TeXt Here}
\section*{What you will learn}
% ref. https://tex.stackexchange.com/a/213707/
% Peter Grill's answer
\begin{curriculum}{Asian curriculum}
\item Number Systems
\item Place value
\item Addition and subtraction
\item Addition and subtraction
\item Multiplication
\item Multiplying larger numbers
\item Division
\item Estimating and rounding Order of operations
\end{curriculum}
\clearpage
\begin{topics}{Statistics and Probability}
\item Data measures Determine mean, median, and range and use these measures to compare data sets explaining reasoning
\item Data investigation
Investigate questions involving the collection of univariate and simple bivariate data
\item Sample space
Construct sample spaces for single-step experiments
\item Relative frequency
Calculate relative frequencies, and recognize variation between results
\end{topics}
\end{document}

ORIGINAL: Based on the MWE & the Image Originally Posted
\documentclass[11pt,twoside,openany,svgnames,x11names,a4paper]{book}% paper added to match image used for testing
\usepackage{wallpaper}
\usepackage[explicit]{titlesec}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning}
\usepackage{changepage,enumitem}
\usepackage{geometry}
\geometry{
% paperwidth=216mm, paperheight=303mm,% changed just for illustration so the background image fits the page
left=23mm,
right=18mm,
top=23mm, bottom=23mm,
headheight=\baselineskip,
headsep=7mm,
footskip=10mm
}
\definecolor{chapopcolor}{cmyk}{.18,0,1,0}
\newcommand\chapterillustration{}
\titleformat{\chapter}{}{}{0pt}{
\ThisULCornerWallPaper{1}{\chapterillustration}
\tikz[overlay,remember picture]
{
\fill[chapopcolor,opacity=1] ([yshift=15mm] current page.west) rectangle ([yshift=-15mm] current page.east);
\fill[chapopcolor,opacity=.75] ([yshift=-15mm] current page.west) rectangle (current page.south east);
}
\strictpagecheck\checkoddpage
\ifoddpage{
\begin{tikzpicture}[overlay,remember picture]
\node (chapter name) [anchor=south west, chapter name] at (current page.west) {\chaptername};
\node [chapter number] {\thechapter};
\node (chapter text) [chapter text, anchor=south east] at (current page.east) {#1};
\end{tikzpicture}
}
\else {
\begin{tikzpicture}[overlay,remember picture]
\node (chapter name) [anchor=south east, chapter name] at (current page.east) {\chaptername};
\node [chapter number] {\thechapter};
\node (chapter text) [chapter text, anchor=south west] at ( current page.west) {#1};
\end{tikzpicture}
}
\fi
}
\titlespacing*{\chapter}{0pt}{0pt}{135mm}
\tikzset{
chapter name/.style={
xshift=5mm,
yshift=30mm,
font=\sffamily\bfseries\Huge,
text=white},
chapter number/.style={
right=0pt of chapter name,
font=\sffamily\bfseries\Huge,
white,
scale=2.5
},
chapter text/.style={
fill=Sienna!80!black,
text=white,
font=\Huge\bfseries,
inner ysep=12pt,
inner xsep=20pt,
rounded rectangle,
xshift=-20mm,
yshift=7.5mm
},
}
\newlist{topiclist}{enumerate}{1}
\setlist[topiclist]{format=\color{blue}\sffamily\bfseries, label=\arabic*}
\newlist{curriculumlist}{enumerate}{1}
\setlist[curriculumlist]{format=\color{blue}\sffamily\bfseries, label=\thechapter\Alph*}
\newenvironment{curriculum}[1]{%
\section*{\color{blue}#1}
\begin{minipage}[t]{0.4\linewidth}
\begin{curriculumlist}
}{%
\end{curriculumlist}
\end{minipage}
}
\newenvironment{topics}[1]{%
\begin{minipage}[t]{0.4\linewidth}\raggedright
\subsection*{\color{blue}#1}
\begin{topiclist}
}{%
\end{topiclist}
\end{minipage}
}
\begin{document}
\pagestyle{headings}
\renewcommand\chapterillustration{enfys}
\chapter{Chapter TeXt Here}
\section*{What you will learn}
% ref. https://tex.stackexchange.com/a/213707/
% Peter Grill's answer
\begin{curriculum}{Asian curriculum}
\item Number Systems
\item Place value
\item Addition and subtraction
\item Addition and subtraction
\item Multiplication
\item Multiplying larger numbers
\item Division
\item Estimating and rounding Order of operations
\end{curriculum}
\begin{topics}{Statistics and Probability}
\item Data measures Determine mean, median, and range and use these measures to compare data sets explaining reasoning
\item Data investigation
Investigate questions involving the collection of univariate and simple bivariate data
\item Sample space
Construct sample spaces for single-step experiments
\item Relative frequency
Calculate relative frequencies, and recognize variation between results
\end{topics}
\end{document}
