I tried readying the stickied thread, but i'm lost.
I want to install mods, im okay with computers and stuff but i am a little confused as to how to install them on my F90-BT. I have an SD card, and i am just wondering what I have to do..
I felt the same way and sometimes still do 
You will eventually figure it out.
yeah but what exactly do i need to do, do I just put the SD card in and then it will automatically install or what?
You need to search on how to get in to test mode. It's on the first post viewtopic.php?f=34&t=18977
If it helps, i made a reply on one of these topics complete with screenshots and file locations