First you need to create a PayPal account.
Note: The Paypal account needs to be a business account, private account is not possible.
After you have created a PayPal account you need to log in to your Braintree account.
When you logged in you want to go to Settings on the top bar and then Processing:
There you find the "Accept PayPal"
Then this should show up:
The first box should say your AppSpotr account, example: firstname.lastname@example.org
The third one is the Terms & Conditions URL
If you haven't made the changes to the URL yet go follow step 6 here
If you made the necessary changes you want to copy the URL and you will find it inside your app under the "E-Commerce" button and the "Store settings" tab:
Copy it and past it into the Accept Paypal in the Braintree account.
Update the information and you are done!
The verification of the Paypal can take up to two days, when it is done it will automatically start running in your app.