You don't thats how you attach the cap on to the top. But don't make it you'll end up hating it (or atleast I did) it is a waste of weed. It takes a large amount of weed to get the high and the high is shit. If you want an efficent way of smoking make a gravity bong it conserves way more weed. If you really want a vaporizer buy one from what I've heard they're worth it.