gumshoe2029 Thx a lot for your new answer
As I said earlier, the free Scirra's signaling server is unstable (probably because there are now too many construct 2 users and it can't always handle it) and sometimes it doesn't work for a long time :-/ (I had some issues when testing tutorial projects, etc... and I read some forum threads where others construct 2 users were having issues with their multiplayer games because of that too) so I don't want to depend on it ^^
It's a very important project to me and I really need it to work at all times, so I'm absolutely sure I need my own signalling server to do that.
My primary goal is not to avoid backend programming at all costs. I'm really glad Construct 2 allows me to do that most of the time so I can focus on gamedesign, etc... but if I have to code a few things to get what I need I will, I just need to learn how to do it ^^
I'm going to take you up on that offer, I hope your tutorials will help me ^^
For starters, look up tutorials on setting up "EC2" for AWS. I would recommend Linux, but you can use a Windows server if you really want.