Note: remember to breathe! This may be a little messy and the first time I almost hyperventilated :)

Here's a blog with lots of pictures - took me a while to find one, although there are probably many more sites equally or better detailed. First one I found, no affiliation - a place to begin :)

Here is a link that might be useful: Dividing AV babies

People will likely give different advice here. When I was first starting, I must have read at least ten different suggestions.

I think we each end up doing what works best for us, because no one is researching it and telling us what's likely to be best.

The best advice I read was to wait until you could tell the individual plants apart from each other. So far, that has worked for me. The dime or nickel rule work with standards, but not with plants that have smaller leaves, so I sort of combine a few rules together:

1. that the outside row of leaves is at least 1/3 to 1/2 the size of the mom leaf,
2. that there are at least 2 to 3 of these larger leaves and at least 2 or 3 of the smaller leaves growing from the crown
3. that the plant looks like a baby AV - I can see outer leaves and inner leaves growing from a crown
4. that I can easily get to the plant without bothering other babies (you do not have to remove them all at the same time; you can remove one and leave the mom leaf to continue growing the other babies)

I hope that helps some. It's just the logic I use.

Now, as to how, that is a bit harder to explain.
1. Remove the mom leaf and gently tap off soil from the roots.
2. Identify the plantlet you want to remove (using the above rules).
3A. If you can, gently grasp the base of the plantlet where it is attached to the mom leaf and rock it gently. This will loosen it from the leaf.
3B. If you cannot grasp it, consider using a clean exacto or extremely clean and sharp paring knife (clean edge with alcohol) to cut the plantlet AND its roots from the mom leaf. This is a bit harder to do, but sometimes I can't get to the plant to remove it by rocking it.
4. Pot the new baby in a small pot; while you can use any size, I prefer using the smallest pot I can for the depth of the root system. Many people put them in Solo Cups or in the cute 2 1/4" pots that Cape Cod Violetry sells. Just do not overwater. Plant it so that the crown is just even with the soil. You may have to prop it with toothpicks if it seems wobbly - there usually aren't many roots to help stabilize it.

I'm almost at this stage myself and found your advice helpful! What do you do with the Mama leaf? If repotted will it continue to make more? Thanks!

Yes that leaf will continue to produce babies.
Happy growing, Happy Holidays
Thom

I have found that a good rule of thumb to follow is to wait until the leaves are about the size of a dime. Then depending on the size of the plantlets I will either gang plant them in a large container using a light soil mix and keep it covered to create a greenhouse effect or put them into small pots and wick them individually. I know that some people cut off the root system completely and treat the plantlet much like a sucker. They claim that it creates a better symmetry on the new growing plant.
Fred in NJ

Interesting. I usually wait until the plants are good sized before dividing them. Like 3" circumference. The reason is that I don't want that many babies. I want a strong plant and the weak ones have usually died by then.
I also cut my leaves on a straight line instead of slanted for the same reason. I then re-pot Mama and start again.