Click Test connection in the Status row at the top of the Paddle settings. The test uses your saved settings, so save your changes first.
You should see Connected to the Paddle sandbox. (or Connected to Paddle (live).).
If you see an error, look it up in Test connection errors.
What’s next
Tick Enable Paddle, place a test order with Paddle’s test card 4242 4242 4242 4242, then follow the Going live checklist.