Thank you all for your concerns. I am not sure where you all are in the world, so for the benefit of Lifeisabeach here is my situation.....
I am in the UK where the statutory mapping outfit is Ordnance Survey. They provide excellent maps at varying scales. I live in the countryside where I am an 82 year old guy who walks his labrador dog extensively every day so am always looking to find additional public paths/bridleways. I have a paper map of my area 1:25,000 scale which I understand is downloadable but primarily for mobile phones and I was seeking to get it on my 27 inch iMAC for ease of viewing and maybe enlarging some areas for clarity because 1:25,000 is the largest scale provided for my area. To do that, Ordnance Survey give a download code when you purchase the paper map. I tried but the system said I needed MAPBOXGL, then another message told me that is not supported by my OS (10.14.6). OK, I might be strangling myself here by not upgrading to OS 11 and beyond where apparently MAPBOXGL is supported, but I also use a couple of photographic applications which will not run under the later OS since the OS bit structure was changed meaning I would need to re-purchase those upgraded applications at significant cost.
I'll certainly study those tutorials just in case, but I am not confident manipulating unfamiliar software - hence at present my view is to stick to the paper map until I can devise a "comfortable" outcome.