We can't tell you where to get games, you have to find them yourself.This is awesome and I've already done it but I have one question. How and where would I put a NDS game in the SD card to play it?
If you followed https://dsi.cfw.guide and installed TWiLight Menu++, you would place the ROMs just about anywhere on the card (the root works just fine, but it may get unorganized) and can run it from there.