If you don’t have a SumUp account yet:

Once you’ve signed up to SumUp (find out more about how to set up a SumUp account for the first time [link to above question], you’ll need to head back to the Starling app to complete the connection process. Go to the Marketplace and Add SumUp again – but this time, choose Login to SumUp.

If you already have a SumUp account:

Go to the Starling Marketplace, tap  on Browse, and select SumUp from the menu. Tap  Add and then select Login to SumUp. Follow the links, which will take you to log into your SumUp account. From there, you’ll be prompted to confirm you agree to sharing the required SumUp data with Starling.