The calculations are straightforward ... but some people, myself included, find it difficult to do calculations when we're just following formulae by rote and don't actually understand what is going on.
I remembered enough O level mechanics to know what concepts such as "centre of gravity" and "moment" were, but the idea of calculating moments with respect to an aribtrary reference point (eg the firewall) rather than actually finding out where the CofG is was a rather different way of looking at it. Plus of course we only bother with front-to-back balance calculations for light aircraft, I never saw it written down anywhere "of course the CofG is located somewhere in three dimensional space, there are monents about it in all directions, but we don't worry about how far off the centre line the CofG is because you can't load a light aircraft in such a way as to cause problems here, and we don't worry about how high up the CofG is for similar reasons".
So what some people might find helpful is not a magic procedure - "stick these numbers in these formulae, plot the result on the graph, and you get the answer, honest, trust me on this" - but an explanation of some O level mechanics that they might have missed out on in their schooldays so that they have some chance of actually understanding what is going on.