The course is free and you can do it on-line. You will have to do certain tasks, (e.g. set up a ipv6 capable mail server), HE will check and if you were successful you enter the next level. If you make it through to sage level you will get a free T-shirt (which in my case they even sent for free to Germany).
The tasks are not difficult but completing the course will take some time. It is hands on experience and I learned a lot. I'm not affiliated with HE in any way.