You can link your C-OPS account to Facebook, Google Play or Game Center after you have played through the tutorial. Just tap your username in the upper left corner of the hub, then tap the social media type you want to link to and give the requested information to link your account.

A Critical Ops account can be linked to all three supported account types, meaning you can link your game account to Facebook, Game Center and Google at same time.

Please remember that you should never share your account details with others. Also note, that nobody from Critical Force will ever ask for your password.

You can also watch this tutorial video regarding account linking