You can convert your Buy and Sell leads to transaction directly in ShortTrack.  Navigate to Leads using the left side menu.  Open the Lead details in the pane by clicking a name.  

On the Lead tab of the pane, scroll to the bottom and click Convert to Transaction.  

Our converted lead is now a transaction. 

The lead is the first contact on the Transaction People list in the new transaction; ready to be assigned a role or added to a team.