Got lot of questions about my sky3ds

Hi guys
First im sorry if my english isn't that good i'm not an english speaker

I've got last 2 weeks a sky3ds , used it to play lot of games in this holidays with just playing 3ds us games

But recently i m trying to do something more with it like playing all regions games , play those ' cia ' games ( don't understand what it is if you can explain me please ) running rom hack games and playing online

So i did some researches and i found some things like emunand , ninjhax , region three...

Got lot of questions about my sky3ds