Adding a new client is simple. First, make sure your terms are set up the way you would like, then navigate to the "Clients" tab. Click on the blue "Add" button. Once that is selected, a window will pop up to input the new client information.
When adding a new contact, you can choose to only run a credit check, or you can run a credit check with payment terms. Regardless, the payment information will be collected.
Under the "Clients" tab you can view the clients you currently have. From here, you can view your client's details, view the agreement between you and your client, and you can also delete the client. Below is an image of what the client details page looks like.