Thank you very much - I think I've started to grapple with it after a lot of difficulty. Following the outdated tutorial(s) caused some problems. I've been looking at the decompilations of QFG1 and QFG2 which has been difficult but instructive. I think I'm now in a position to make something rather than figuring out the programming basics, so I'll see how that goes. Though trying to draw a basic room with things vaguely in proportion has proven to be about as challenging to me as anything else.
You might also want to check out Betrayed Alliance. SlattsStudio created it and it is free and he included all of the SCI source code for it.
https://github.com/Slattstudio/BetrayedAllianceBook1/releases/