For anyone playing who needs the controls:

WASD to move

Spacebar to take a customer's order and collect ingredients

After getting them from the fridge, you have to put the burger patties on the grill and wait until it says they're finished

Once you have all of the ingredients for an order, assemble them at the cutting board with Spacebar

Then go deliver the burger with Spacebar again

E opens your supplies/upgrades menu