First, power on your SM-L300 printer, load it with a roll of thermal paper, and connect it to your PC with the micro USB cable provided.
Click the following link to go to the Star Micronics drivers page:
Once the file StarPRNT_Mobile_2.2_setup.EXE is downloaded, run it.
Run the Portable Printer Utility. Select SM-L300 and follow the prompts.
Next, run Control Panel, click on Device and Printers, and check that Star SM-L300 is visible under Printers.
Finally, run a test print in Box Office. Make sure you have the following settings on the print preview page.
Please note that the preview of the ticket itself will look extremely long. If you're printing out multiple tickets, there will be very large gaps between each ticket. However, the ticket(s) will print out correctly without the large blank areas!