I'm not able to play the games =(

I downloaded 2 games, one from GBA and the other from N64, i dunno how i can start running the games, when i extracted the games theyre just simple files, where i can get a program to install them?

In order to play games on your computer, you need an Emulator. Emulators are programs that Emulate (act like) the consoles/systems that the games were made for. Some emulators run very well, others not so much.Take a look in this thread and download the emulator for your system.
https://www.romulation.org/forum/index.php?topic=1535.0For GBA games, you should use Visual Boy Advanced. Take a look in this thread:
https://www.romulation.org/forum/index.php?topic=6326.0For NDS games, you'll want to use No$GBA 2.6a There are links to it in this thread:
https://www.romulation.org/forum/index.php?topic=1462.0

Hehe, yeah as Tirith said you can just "run" the files.
The GBA emulator I use is VisualBoyAdvance and I use Project64 for N64 roms.