Providers can be managed via Settings > Providers.
Here you can select which payment provider you would like to connect. Please note that you will need to have created an account with the external provider to connect it with Pest Register. This can be done by heading to their website.
Once you have created your account and set up the system you can click on the connect button to the right-hand side of your preferred payment provider.
You will then need to authenticate your payment provider and confirm the link with pest register.