I know 500 miles is not a big deal :) but better than nothing since AA does not have Signup bonus normally!
Visit www.aa.com/enroll and sign up. **For sign up a NEW account ONLY!
Then go to www.aa.com/offers and enter AADVB
the miles will post in weeks.
***UA normally have more signup bonus. Now they have those bonus by referral only! So ask friends around to see if they can refer you. Both sides can get 1000~3000 bonus miles.