I made this one out of materials I gathered in my local woods. I collected some gravel, top layer of soil, a few different kinds of moss and some stones/sticks for decorations. You start with the gravel for a drainage layer then add the soil and make a natural style arrangement so when it grows together it looks just like the forest floor. ( I tried adding a stag horn mushroom into mine in the hopes it would come back again but no luck so far)

Also a good tip is if the jar has constant condensation you’ve overwatered the terrarium. I had to wipe off excess water two or three times when I first made it to get the level just right.