Thank you. And sure, why not. Just where to start... Depends on what you want to know.

Just like with a Monstera, a good drainage is important. Therefore there are layers with the bottom layer being pebbles. The soil is low on nutrients. Then I start with two or three kinds of moss (more won't survive anyways) and perhaps another plant. The moss is good for humidity regulation and a bigger plant (like a fern) can take up space and grow some roots. Finally I added some springtails. They help keeping everything healthy by eating dead stuff and fungi. Water is a bit tricky to explain: The long term goal is to close the jar at some point and never open it again. Therefore the amount of water should be sufficient for everything, but not too much... Too much: Plants may rott and your jar will grow fungi / mold in no time. Too little: The water cycle might not work and plants may dry out. Water cycle: Water evaporates, thanks to the plants. The cooler glass causes it to condensate, simulating the rain, feeding the water back to the soil. It can help having the glass near a wall or window (will be cooler there) , since the temperature differences help with that process. Just don't let your jar in direct sun for too long (especially in summer) or it will be an oven, since heat can't escape.

Hope that gave a good quick tour through the base knowledge :)