From your username, choose Settings/ Integrations/ HaloPSA and choose "Configure" for a new integration, or "Details" to change an existing one.
In HaloPSA, navigate to Configuration/Integrations/ HaloPSA API. Choose View Integrations, then "New".
Application Name: enter a name relevant to you, such as your company name without spaces.
Authentication method: Client ID and Secret
You will see displayed a "Client Id" and Secret. Copy and paste into Datagate "Client Id" and "Secret".
Back in Halo, choose an Agent that the API will use. Press Save.
In Datagate, enter the Tenant. This is the Application Name you entered in HaloPSA.
You will find the Resource Server and Authorisation Server in Halo, in Configuration > Integrations > HaloPSA API.
Enter these in Datagate and press Save.
Once you have saved your settings in Datagate, press "Test Account Access" to ensure your settings are correct.
"Test Account Access" will also create a Custom field (Datagate) on the Customer in HaloPSA.