Ahh mate.
Here we go:
1) Get a micro SD card. ( I use non - SDHC and it's perfect)
2) Get AKAIO from
here. Make sure on the right side that it is the latest. By the way there is a disabled one up so don't bother clicking it.
3)Extract AKAIO on your empty and formatted Micro SD.
4) Just for neatness, create 1 folder on your Micro SD for Games and Homebrew and 1 Folder for music and movies.
5) Get roms or homebrew. (Piracy not recommended but it's your choice) You'll find LOADS of homebrew on Gbatemp. Remember posting ROM requests or how to get roms is forbidden on gbatemp, stick to the rules
. When you download them, put them in the games and application folder on you micro SD
6) You can put music and movies in the folder you made. I think AKAIO already has a feature to play music, i'm not so sure cause I don't use my DS for music. If not, get moonshell (it's a homebrew). It plays movies too , but I'm not sure which format. Check that on google or something.
7) Tell me what happens.
OH BTW:
If when you put the Acekard into the DSi and there is a picture of Danny Phantom or the Picture of AceKard 2i, you need to update it by finding the thread on how to update it which should still be on the homepage of this site. It's easy so you won't face any problem.
Hope I helped.
You're welcome