Moss can be grown indoors if the conditions are right. Take note of the environment the mosses naturally grow in and do your best to replicate it. Larger pieces of moss are more likely to survive, so make sure your sample is as big as possible and firmly press it into the soil. Mosses don't need rich soil and can grow in sand or on the side of a terracotta pot. Full sun will likely dry them out, but they do need lots of light and lots of moisture. Sealed in a terrarium, the moisture will allow the moss to thrive, but a plastic bag will also do the trick. When they begin to dry out, mist them with clean de-chlorinated water as mosses are very sensitive plants. Try a few different verities and plant them in a few different ways to see what works. Most of these mosses ended up in this terrarium here https://youtu.be/vUMXd3dr5bI.
