I installed some CCTV cameras last year, but I don't think I've written anything about it, so you won't find this on a forum search.
One important consideration is how you're going to power the cameras. You can get battery-operated wireless cameras but I wouldn't have thought they'd be suitable for a permanent installation. So you need to get some wires to each of the camera sites, and that might affect your choice of locations.
Another important consideration is how you're going to get data off the cameras and where it's going to go. Wired or wireless, local storage or cloud? Personally I think wired cameras and local storage is likely to offer a more convenient solution, but in this respect YMMV.
Putting these two strands together, I decided to fit cameras that used Power-Over-Ethernet (PoE). So they have just the one cable that carries both power and data. I bought this system from Amazon:
https://www.amazon.co.uk/Surveillance-Megapixels-Security-Ethernet-Smartphone/dp/B01F4PQQYE/
(There are lots of similar systems from the same manufacturer, Sannce. They differ in details like the camera resolution, camera style (bullet or dome), cabling technology (PoE or coaxial), hard disk size etc, so make sure you read the details carefully.)
It was very easy to set up, and everything worked first time. The user manual is a bit Chinglish and the smartphone app isn't the smartest, but it does work.