You'll be taken to the Edit tab to choose the general settings for your reward. Set up your title, instructions, and copy/paste the link to your rules and restrictions page.
You can further customize what your reward page looks like by clicking on the "Customize" tab. On this page, you can upload an image for your Fan Gate and a custom voucher page, as well as the rules for your contest. After your content look the way you want, you can also opt to change the way the buttons look by clicking on the "Buttons" tab.
Now, let's click on Form Fields. This is where you can choose what data you want from a user in order for them to participate. There are many fields in the dropdown menu to choose from, but with a checkbox or text field, you can customize it to say whatever you need it to. Underneath standard choices, you'll see options that will require Facebook Authorization Dialog. This means users will be prompted by Facebook to give permission in order to share their data.
Finally, you'll need to click Facebook Page Tab, where you'll choose your tab name and image.
Your Reward is ready to go! You can take your promotion out of admin-only mode in the "Edit" tab and start collecting entries. You do have additional options you can play with under the Language, Sharing, and Customize tabs, but this is enough to get you started.