Hi,
> I'm still not sure about how to change the PO-Revision Date, or how to
> include previous comments. Would the comments show up if i worked on a
> previous ru.po file?
The best would be to get the appropriate existing ru.po file
(right-click on the corresponding "raw" in the git repo and chose
"save file as..."), or get the .pot file (the same way) if there's no
existing ru.po file and rename it to ru.po, and then open it with
POedit in order to work on it.
This way, you shouldn't have disappearing comments or PO-Revision Date
issues.
Anything you could need may be written in that page
https://tails.boum.org/contribute/how/translate/
Cheers