In order to start setting up your Abstract module, you need to activate it form the Registration Form Setup.
Click on YES to the "Will you collect any abstract from your participants?" under the Abstract Preferences section.
After that, the abstract module will be displayed on the left menu. Now you can start the setup process.
Also, you can start your Abstract Form Setup from Registration Form Preview. You will be forwarded to your Abstract Form Setup by clicking the Abstract Form Setup button.