Every kit has a guide, and every guide is public before you buy. Read the one for the system you are considering — if any step looks like more than you want to do, tell us and we will come and do it.
Plan, place the recorder, run cable, mount, connect, set up, view on your phone. The same seven for every kit.
One network cable per camera carries both the picture and the power. Nothing you install touches household electrics.
These are the jobs we do for a living, including the placements we end up correcting on almost every one.
Send a photo of what you are looking at. That is usually all it takes.