Alright I will explain, Get on Wifi First.After connecting, choose the second Icon(Two people with DS's). When you are there, wait for a room and select one.
First, you need my friend code though, to do that, go to the Wifi option on the menu screen, go to the second option, then the second option again. You should see 4 options now. go to the third one, and tell me the numbers you see there. After that, exit and go to the 4th option and enter this 2449 1557 8157.