Step 1: Click "Manage Participants"
Step 2: Click "Edit Participant Registration Form"
Step 3: Scroll Down To Custom Field 1. Click on the Gear Box to the Right.
Step 4: Add Your Field Title. Choose if You Want it Shown on Your Website and If the Field is Required. Hit "Save" When You are Finished.
Step 5: Click and Hold the Three Circles to the Left of the Question and Drag The Field Where You Want It on the Form.