I enjoyed the video tutorials on your website. Have you ever made any step by step tutorials for online Multiplayer? If not, do you know of anyone who has? Videos make a bigger impact for me vs reading.
For now, I would recommend playing around with the templates. It can be overwhelming at first but Construct 2/3 does a lot of the heavy lifting for you - try to focus on figuring out how syncing objects and sending/receiving messages works. It becomes quite simple the more you progress. I'd be happy to answer any questions that you might have.
All that said - don't bother using Construct 3 for Multiplayer unless local preview gets added: https://construct3.ideas.aha.io/ideas/C3-I-314
Construct 2 is your best bet for now.