New to 3ds/3dsxl homebrew.Some help please?

[lolcox]

Ok so I do have two 3ds:
1. Old 3ds v 9.0 Eu
2.New 3ds xl v 9.2 eu Browser Version 1.0.9934
I found out I could use at least 6 exploits(3 game exploits and 3 system exploits) for the second one but not only didn't I understand how to do that,I also didn't understand what were they used for.I mean, what do we gain homebrewing them? Do they work same as Gateway 3ds flashcard which makes you play 3ds games by downloading them?
Also,I do have a Gateway 3ds flashcard for the first one,but I've lost the blue cart so I'm left with the red one.Can I do something with that alone,or should I drop it?
Thank you!

[Dione1109]

Q2: R4 card has the same function with gateway blue card. You can get a cheap r4 card to replace it. Such as r4i gold 3ds, ace3ds plus, r4i-sdhc 3ds rts.