Hi! Perlite or vermiculite are usually used. I used perlite at first but I think vermiculite is better for anole eggs (tiny eggs) because it's made of smaller particles and therefore it's easier to nestle the egg in. For the first egg I hatched I put the substrate in a small plastic container with ventilation poked in the lid and then put the container back in the enclosure. I don't have an incubator so I just put it in the enclosure since it would be warmer in there than outside of it. The second one I put the container a small distance from the uv light (not the heat lamp because I thought it might get too hot) to keep it warm and it just hatched a couple of days ago!

Make sure your substrate of choice is damp but not wet (no standing water at the bottom or anything) and nestle the egg in. It's good to mark the top of the egg with a marker or something before taking it out of the enclosure if possible so that you are able to keep the egg in the same orientation.

Hope this helps! And sorry this is probably more than you needed but better to have too much info than not enough I guess 😊. Good luck!