Deals feature will help you to find in one place coupons (voucher codes) and promotions from advertisers. To be able to use this feature in the Dashboard and the API, you will have to subscription to the Deals on your subscription page.
Good news, for most of networks you don't need set a new connection, but for some of them you will have to add more informations.
Go to Manager, Networks and click on the tag icon :
Then you will have a to fill in credentials to add the connection :
For most networks, it is not necessary to add additional credentials, but here is the list of networks that you will have to add specifics credentials for Deals: