Step 1: First create a Billit account, if you don't have one yet. As a new Billit user, you can try Billit free of charge for the first 15 days. After that, you can choose a licence tailored to your business.
Step 2: Also create a Simple Simon account and log in. You can use it free of charge for 14 days. On this overview page, you will find all the steps to install the integration.