sign into VGCollect first goto HOME then hover over the magnifying glass, type in name of game hit search, pick a game version, than click on it title text. then when the screen loads click on add to collection button.
if you want to see all games listed then
goto HOME section of this site, then click browse then pick a device, then click on a game in the list, then click the add to collection button
you can only add 1 at a time