You need to create a product group to add products to your profile.
Here's how if you haven't already set it up.
Add a Product
If you go into the product group, you will see something like this:
Add a product by clicking the add icon above Create product.
Based on what category you chose for the group, the product will ask for different information.
You can enter your price for your product. This could be based on CPM, Price/time period, set price or list contact seller for media buyers to contact you for a price.
If nothing matches, you can always pick other to match your unique product.