Ahh I see. Well once you’ve downloaded Project 64 V1.6 (which acts as the Nintendo 64 console), you have to go by downloading ROMS. ROMS in this case are the actual games.
There are many ROMS available. You can also play online 
(Super Smash Brothers, Mario Kart)
Anyways, I recommend playing Zelda: Ocarina of Time. One of the greatest games of all time !
http://www.coolrom.com/roms/n64/7967/Zelda_-_Ocarina_of_Time.php
If you want other roms, then visit: www.coolrom.com
Other fantastic games include:
Super Mario 64
Conkers Bad Furday
Banjo Kazoozie…
and the list goes on and on
Once you’ve downloaded the ROM (extract it if required), open Project 64 and open the ROM using the emulator. Then you’re all set to play
and unfortunately I don’t have skype x) Happy gaming!
(Make sure you have the latest v1.6, or else you might end up getting those memory errors!)