First, start big. Get the basic shapes right with large lettering. Ideally you would have something you are comparing to like a stencil or grey printout so you can see the difference between your writing and the target.
After you have the shape fairly good large you can shrink it down. You can take your time getting to that and just make a little progress at a time.
If you find it impossible to shed your current handwriting consider using grid paper to force spacing and maybe try your non-dominant hand.
I don’t know about videos but having a look at the OSI model is a good way to start. It covers the abstract framework for packetizing data including things like the distinction between hardware and software, envelope, encryption, application layer stuff, the whole shebang. The cool thing is by going hardware, network, application you can see where responsibility are and it helps you understand where things can go wrong.
If you are interested there are plenty of CCNA style courses available on the internet, licit and otherwise, and they go into more depth, and the same applies to RHCE/RHCSA material. The training for certifications like that covers what you want to know but also puts it in context, and again licit and otherwise sources are available.