How to Link Go High Level CRM to Service M8

Hi I have just purchased Go High Level CRM and I have added the Service M8 plug in to GHL. At this stage nothing is linked to each other. What is the process to be able to link my Service M8 account to GHL so i can both import my contact details from Service M8 ( my customers Emails & phone number) and add info from new customers into SM8 from GHL