The easiest way is to use a tube bender which costs around $400 on average. You insert the tube into the bender and make sure you're bending it at the correct point. And then set the bender on how many degrees you want to bend it, and then turn it on and the machine will do its job. You can also use roller stands or a heat gun to bend it, which are cheaper but it's just a lot easier to use a bender.