my nds-tti only takes nds files

hi im new here and just need some help
how can i get my nds-tti to allow rar files to work on it? i tried using this program but i can only go to ndsr.net and the games i want there are a bit dodgy could someone help me?
and also what are emulators?

Use WinRAR to extract the .nds files from the .rar files

thnx for that mate but how and where do i download winrar?

Here
http://www.rarlab.com/download.htm

which 1 should i downlod and how should i download it? i dont wanna pay or anything

Download the latest one?
After like 30 days it'll nag you to buy,but don't worry as you can still use it.
It'll just nag :D

i've decided to get WinRAR x86 (32 bit) 3.90 and save it to the desktop as an application and how would i get the files to work on my tti after?

Have you installed it?
After installing it you can extract the game from the RAR file.

ok sweet!!! thnx mate !!!!!!!!! ;) :D ;D