When setting up clients, it is important to setup the services they will receive.
To start, go the client(or add a new client) in the 'Client Information' screen. Open the 'Services & Add-On's' tab as shown below. There are a list of services and add ons that you can choose from in this tab. Select the services that the client will receive.
For example, if you don't select the 'HPC' tab then the client won't show up in the HPC screen when documenting. This can be done in the initial client setup when you send over the client templates with their basic information.