You can convert Leads in FastGem into Customers by changing the Workflow status (Status of the Lead/Customer) to a 'Passing' status. Statuses can be customized by contacting Support at 504-383-0602. 

See the screen recording provided below (click the link) to get a visual explanation on doing this one of two ways. 

Leads can also be converted from the Overlay tools by putting the work flow status to a passing status from the overlay. 

 

Converting Leads into Customers