Go to the webpage https://developer.paypal.com/

Log in to your user on the upper right part of the screen to enter the Dashboard.

On “My App & Credentials” you can create keys on both “Sandbox” mode and “Live” mode. This means“Sandbox” are keys for tests and “Live” for production mode. Both have the same steps except they are created in diferent tabs.

Click on the “Create App” button to generate a new app to receive payments.

Complete de App name and click on "Create App"

The Client ID will be generated and you can see the Secret ID by clicking on "Show", this 2 values will be needed to configure Paypal on Rently. Next sign in to Rently's backoffice.

On the upper left hand menu, select the "Box" menu.

Next look on the leftside menu for the option "Payment Methods".

When scrolling down you will find the Paypal box, click on "Manage Credentials".

On the next window, click on New to create new credentials.

Complete the fields and use the "Test" field if you wish to use it in Sandbox mode and test payments.