First, a warrant class will need to be created. This class holds the shares for the warrant in reserve until its time to convert the warrant. Then the reserved shares are issued to the warrant holder as a stock grant.
To add a warrant, go to the Quick Create menu, + icon on left panel, and click Add Warrant. Name the class to your preference and reserve the number of shares needed to convert the warrants. Clicking "Submit" at the bottom will bring up the Issue Warrant page.
Here, enter the details for the warrant. Then click Submit to finish the issuance.