Get a long pole, and teach them with that. It works fairly well.....just tap the ground to the side you want them to turn
from......... or keep it up if they are going well where you want them to go. Start with the pole at a great distance until they get used to it....then you can gradually move the tapping pole (or just held low horizontally) closer to them...after a bit, it becomes pretty fine tuned. Just don't crowd them from the back....stay just at about the edge of their personal space...to make them move forward...but don't actually 'intrude' on their personal space.. this moves them forward, but at a slow duckie waddle, not a hurried one.
It helps to start with short distances, and to have 'hidden' some treats where you 'herd'
View attachment 3022303 them to for the first few weeks...soon they will be herding reasonably well!