If you have cash drawer management enabled, you have the ability to open your cash drawer through the Cents store application on-demand.
Simply click into the navigation menu on the Cents store tablet application, and click on "Cash Drawer":
Click into the 3 dot menu in the top right-hand corner, and select "Open Cash Drawer":
Your printer will print two small slips of paper, and the cash drawer will open thereafter.
If it's not opening, make sure to check the following:
Ensure your cash drawer is unlocked
Double check your cable connection from your printer to your cash drawer (and make sure it's plugged into the beige cash drawer port on your printer)
Confirm your printer connectivity via Bluetooth or Ethernet
Take a look at this video for a detailed tutorial on how to open the cash drawer: