Go to the help menu and select “Register this Machine” enter your email and password that was emailed to you. More info on registering can be found here:
https://mainsequencesoftware.com/Content/SGPHelp/Management.html
Also sounds like you may have installed multiple copies and something potentially was messed up in the process if the application is not launching. You may want to look here to try and clear up the error: SGP will not start after trial and paying for full program - #20 by Ken
Jared