1. yes, it's in the user guide [1] 2. Git LFS should work, yes. Care to try and report back ? ;) Open a new topic on the Zulip #Support channel [2] if you run into any issues.

[1] - https://radicle.dev/guides/user#4-embracing-the-onion [2] - https://radicle.zulipchat.com/#narrow/channel/369873-Support