"Potty training" assumes that children want to be dependent on someone else for being clean and dry, and do not want to copy their elders. I think this attitude is mistaken. Many small children dislike being in wet or dirty nappies, and many very small children carefully tear off small pieces of loo paper to put down the loo, while they aren't raising or lowering the lid or trying to pull the flush lever.
Once children begin to get physical control over peeing and pooping, and begin to be consciously aware of the sensations of needing to go and going, there are two ways to proceed.
1) Frequently sit child on potty and celebrate with mexican waves, gold stickers, or new bicycles when child performs. Child will quickly learn that this is something very important to hir parents, and it will therefore become a source of anxiety or an opportunity to exercise power over parents by refusing to go, or going elsewhere. Much anxiety and misery all around. Eventually child learns to use potty/loo.
2) wait until child expresses an interest in no longer wearing nappies. Explain the system. Clean up accidents with an "oops, never mind". Child will probably get the hang of it at approximately the same time as in system 1), or slightly earlier, with no stress, and OWNING the triumph of a self-directed step towards independence.