We have a decent Construct 3 Manual which is enough to educate us. The Remote Preview is quite straightforward. You preview from one computer to another device, let it be a PC, Mobile or a tablet.
The manual is fine for self-education, but sometimes it's nice to see things running in a real world setting and not just in theory.
Anyway, I upgraded to a C3 account and am glad I did. The three features I mentioned in the original posts are all amazing, I'm just not sure why Scirra don't either release some marketing videos to show this stuff in action or enable them in the trial version as they're pretty massive improvements over C2 imo.