How to contribute to the GIMP manual and quickreference translations

Hello, I’ve noticed that parts of the Russian manual and quickreference for GIMP are not translated.
I am curious, what is the process of submitting translations and if there are any specific guidelines?

You can join the Russian team and help them. Make sure you read the documentation and follow the links in the team presentation text.

The GIMP documentation is listed in the table on that page as well.