First off⦠donāt let my comment bother you. If I canāt use glass thatās fine by me. Itās one of those if you can, cool, if not there are other options and it being cdda, lots of other options! 
As to compound arrow. Basically you have a shaft with a socket in it and then a variety of heads each with a small shaft that fits in the socket of the shaft. The reason being twofold. First, the arrowhead tends to break, but the fletching and shaft tend to remain OK and this means that you can just make a new arrowhead and socket it. Second you can carry more than one kind of head and swap them on the fly. The classic being a sharp stone head and heavy wood blunts. So if youāre hunting a grouse and a deer shows up you just keep the arrow knocked and swap the head.
Look up āIshi Arrowsā They are fascinating, but as I said probably out of scope for this game.