Plumbing water to an icemaker is very straightforward. It’s hard to say what situation you will be dealing with. You may already have a valve behind the refrigerator, or you may have a copper line stubbed off.
The refrigerator/freezer will usually come with an installation kit which will include a water line and sometimes a filter. The issue though is getting the water from the wall to the icemaker.
If you have a copper line coming from the wall, you can use a plumbing valve with a compression fitting on either side of it. You will need to remove the cap on the copper line and slide the nut from the valve over it. Then slide the ferrule onto the end of the copper line. Push the copper line into the valve and tighten the nut over the ferrule so that the ferrule compresses between the two. Repeat the same procedure on the other side of the valve connecting the water supply up to the icemaker. Tighten all fittings snugly and then turn on the water.
If you are using a filter, run a couple of gallons through the filter to wash out any debris before you connect it to the icemaker. This is easy if you are able to get water from the door, but if not, point the line into a bucket and flush it out.