How do I set the space size around stuff and various (title, legend, …) font size to specific values in my document? [closed]

Question

I have to follow these very strict and boring rules.

• Like the article class: neither title page nor table of content.
• No heading/footer on the first page
• Following pages must have:
  • small text (school name) and the year as a heading, 10pt
  • the authors on the left and page number on the right as a footer, 10pt

Now the various space/size requirement:

• Default font: 11pt
• Margin: 2cm
• Title: 16pts, bold, space before 12pt, space after 12pt, centered
• Level 1 title: numbered, 14pt, space before 12pt, space after 6pt, left aligned
• Level 2 title: numbered, 12pt, space before 6pt, space after 6pt, left aligned
• Level 3 title: numbered, 11pt, space before 6pt, space after 3pt, left aligned
• Authors: 14pt, bold, centered, space before 12pt, space after 12pt, centered
• Date: 11pt, space before 0pt, space after 12pt, centered
• Figure: space before 6pt, space after 6pt, italic, centered
• Legend: space before 0pt, space after 6pt, centered

I'm using the french babel package ([francais]{babel}), don't know if it's relevant.

Here's the description of these rules. It's in french but it should give you a (visual) idea of what is expected.