I have read the manual and try the
\setuphead
[chapter]
[page=right]
but it has no effect :-(
You probably use a single-page layout. Right pages only make sense in double-sided layouts. The following works here:
\setuppagenumbering
[alternative=doublesided]
\setuphead
[chapter]
[page=right]
\starttext
\startsectionlevel [title=Foo]
\stopsectionlevel
\startsectionlevel [title=Bar]
\stopsectionlevel
\stoptext
Alternatively you can define a custom page break with \definepagebreak. Example:
\setuppagenumbering
[alternative=doublesided]
\definepagebreak
[chapterpagebreak]
[yes, right]
\setuphead
[chapter]
[pagebreak=chapterpagebreak]
\starttext
\startsectionlevel [title=Foo]
\stopsectionlevel
\startsectionlevel [title=Bar]
\stopsectionlevel
\stoptext
\setuppagenumbering[alternative=doublesided]
.