You can set cash drawer from settings of Repair Desk. Please follow the given steps to do this:-
Click on Settings Icon in the Module configuration >> Cash Register Settings >> Cash Drawer Settings >> Save Changes
Cash Drawer settings are based on currency, value and positions in cash drawer to keep all the currency.
There are default cash drawer settings in $ currency. You can edit it based on your own currency, value and position of cash drawer. You can also add new lines to set it.