There are many types of cash registers available. The newer ones are electronic while some of the older ones are mostly mechanical. One thing they all share is a similar setup process:
Decide on a location for the cash register. It will need to be a hard flat surface. This is to avoid it falling or slipping off the surface.
Make sure the cash register is not under an area where you will be handing customers liquid items. If that is not possible then get a plastic sheet or cover for the unit.
Plug the unit directly into a wall outlet, do not use an extension cord. Do additional wiring if necessary.
Under the receipt paper cover area should be a location for batteries. Check and install batteries if there are none. These batteries maintain the device memory during a power outage. Please note that these batteries are rechargeable.
Lift the receipt compartment cover and feed the roll so that it runs out through the front of the register. This makes it easy to tear and handover to customers.When you take the paper roll, check and ensure that it has a straight front edge.
Keep the key for the till drawer lock in the drawer itself. This way it can be quickly located and locked when you need to.