Windows documentation?

Is there some sort of (hopefully detailed) documentation for Windows anywhere to be found?

I am building a new machine and while I'm waiting for some parts to be delivered, I am gathering my software and license keys and all that. With the new machine I will be forced to make a complete transition to Windows 10 (previously I used it only for my own education, my primary working machine has been Windows 7). One thing that irritates me about Windows 10 is that every little routine wants to access the internet all the time. Perhaps I am getting old (which I am), but I want to control which routine connects the internet, when, and for what purpose. I control this by using a firewall (ESET in my case) which reports to me when something on my machine wants to access the net (originally the firewall was to keep outside intrusions at bay, but lately it's the other way around). If it's a program I know (such as Word) than I can easily make a decision (e.g., Word should not be accessing the net on a daily basis, maybe once a few months when I'm searching for a new template). But there are lots of cryptically called "system programs" that try accessing the net all the time and I have no idea what they are and what is going to happen if I block them. Searching the net each time this happens takes too much time and effort, therefore I'd like to have a single reference resource, where I could check whenever I have a question like that, hence the question above.

My feeling is, the reasons for apps and services to access the internet are not limited to updates. Moreover, I'm not really talking about apps, I'm talking about system processes. I could give examples, but I'd like to avoid discussing details of each particular process. My primary concern here is to find some reference (ideally - documentation) on what each of these processes do and why do they connect to various servers, as well as how can I control their behavior in the best possible way.