You can't anymore, they removed it when they announced the shutdown and they don't have any plans on bringing them back.
https://www.seriousgmod.com/threads/global-ranks.51091/#post-539744 basically, you cant get legendary anymore, the yearly ranks were removed from the store because of the shut down, and frankly there is nobody who can tell you for 100% certainty if gmod will be around for 1 whole year from now, so theres no point in highwon bringing back the yearly ranks that's not to say they WONT be back, its just unlikely