To start sell your items, you need to connect your PayPal account.
To do that:
1. Open Administration panel and go to Vendors → Vendors.
2. Click the name of the vendor.
3. The vendor editing window will open. Scroll down and fill in all the fields in the PayPal Payments section.
4. Enter data and click "Save".
5. After the changes are saved, the it will automatically requests confirmation from PayPal that the provided email addresses are valid for transactions.