Converting AR codes to something BizHawk understands would require looking into the AR code format and seeing what the code exactly does. If it's just freezing some memory address unconditionally, it's relatively trivial to do the same in BizHawk with its own cheat interface. If it's doing something more complex, it may require some lua scripting in order to implement it.
.SaveRAM files are .sav files with a different extension. Importing .sav files is nothing more than renaming them and placing them in the correct folder (NDS/SaveRAM folder)
I assume you just want a place to save whatever TASes, whether complete or not, onto the site,
and not what we typically refer to as publications (a completely separate ballgame). You probably want to just look at the
userfiles here.
For adding resources to a game, look at the game's own
game resource page. You may need to ask a staff member for editing permission on game resources here however, as you lack the Published Author role which normally is what gives permission to edit game resource pages.
