Log into your new account. Then go to My Clubhouse in the Main Menu...
In My Clubhouse, click the ENTER SCORES button.
On this page, you will enter your last 5 rounds of golf, one at a time. If you don't remember the exact scores on front and back, just split the total somewhat evenly between the two nines. The slope and rating for each course can be found on the scorecard or on the course's website if you don't have a card.
Once you submit your first score, you will see this screen. Click "Add another score". Repeat this until you have 5 scores in and then you will have a handicap on the site.
Once you do that, you can register for your first event!