So, I would like to know how to get the players height from the ground? Its pretty simple Thanks in advance!
Also if anyone can help too, I would like to know how to spawn a entity such as In aac that follows behind you
Loop through the blocks down in the Y axis of the player, counting up until it detects a block that is not air.
If you have to ask the first question, you should probably go back to learning java and researching the bukkit api. As for the second, there are a few ways. Giving it custom pathfinding via NMS (the proper, harder way), or using a runnable to constantly move it (the easy, ugly-looking way).