Yeah, learning those things will definitely help, with all future coding, no doubt; thanks! JS in Sublime, then run in Firefox works (at least with some codes!). Following Shiffman, some codes work perfectly, and other don’t until I mess about and tweak and try a couple different things; but generally they do work, until it gets really complicated.
I do wonder though, about how you set up the whole thing. To use the p5.js etc. one video said to have the folder on the desktop, which I don’t understand (except that it worked when I did it, haha). Is this the same for other readers or coding languages? (Because I tried everything in p3 and nothing happened except a load of error messages! I assume I need to set it up differently?)