Can anyone help me with my R4?

Ive loaded a game on my micro DS but but when I tried to find the game on my DS by pressing A it wasnt there. What am I dong wrong? also, what is the adapter for and where does it go?
This was the game I was trying to upload - 0168_-_Mario_Kart_DS_(U)(SCZ)(D47555BE).rar
Any help would be appreciated - also im not very technical minded when it comes to these things so in leymans terms would be great.
Thank you, please help!

You need to extract them to get the .nds ROM file. https://www.romulation.org/forum/index.php/topic,3880.0.html

Thanks so much! :)

I had the same problem. now wen i download games the touch screen wont work 4 most of them can any 1 help pls!!!!!!!!