We can help you with homebrew, but not with backups; they are illegal whether you own the game or not, and therefore they are a banned topic on these forums.

Q1) You need a USB cable, a computer and an internet connection.
Q2) It's easy, you just need the files for the homebrew, then put them on.
Q3) I think it supports every homebrew game and MSs up to 2gb (might be 4gb, not sure).

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