The installer will install iRacing Setup Sync Launcher, which takes care of automatically updating iRacing Setup Sync to the latest version.
You need an account on the setup database website which you use to login to iRacing Setup Sync.
Create your account here if you do not have one already.
Once your account is created you need to confirm ownership of the account by following the directions in the iRacing PM you should have received. You will not be able to login until you have confirmed your account!