This can be accomplished by adding giving levels to the form. 
  1. Log in to NetCommunity
  2. Edit the donation form part
  3. Click the Edit this page button in the upper left corner
  4. Locate the gear icon that is for the Donation Form Part
  5. Click the Gear Icon for the Donation Form Part
  6. Select Edit from the drodown
  7. Scroll to Giving Levels
  8. Click Add Giving Level
  9. Add the Display Name and enter the amount
  10. Repeat for the other levels
  11. Click Save when finished