Well to answer your q2 I suggest to use svn and you can download any version you wish included examples and documentations. here is the link for svn:
svn.opentelemac.org/svn/opentelemac/tags/v6p3r0/ and you can find the same in the
www.opentelemac.org/index.php/sources-svn where user and password located. yes I believe the precompiled version is now available for the two latest version of telemac. However, if you wish, you can install the latest one and then download the source code through svn by creating a file inside the telemac directory and named as exaple v6p3 and then right click and then svn checkout then paste the link of svn above and user and password. after that use command prompt and having proper config file you will able to compile that version or any others. use compileTELEMAC.py
to start with telemac2d is always advised to read the user manual as a beginner and navigate through examples and validated cases using notepad++.
Hope this may help
AMANJ