I’ll try and put in a very basic form Juddian
If your going in a straight line ad for example both wheels are doing 100 rpm each ,so that is a combined total of 200rpm.
If you then take a bend then the inside wheel ha to slow down and the outside needs to speed up…So as an example the inside will slow down by 25rpm as it is taking a tighter turn and that 25 rpm will go to the outside wheel …So you still have your combined total of 200rpm.
The transfer of RPM is done through the differential,Thats for another day JUDDIAN lol
Another analogy which ex forces will recognise is when they are marching ,If again going round a bend the man on the inside will then take shorter steps and the outside man takes larger step,if they didn’t it would be a bag of ■■■■…And if the diff didn’t do it’s job it would try and push the vehicle forward
Has that helped lol