Push through the first door then there’s another door which you’ll be buzzed through. Then pay your entrance fee, the guy will ask if you want a large or medium towel, I would recommend medium. You’ll also be given a locker key, you can stay as long as you like. Go through the next door and you’ll see the changing area and lockers. Get changed, put your stuff in your locker then explore. Three floors with different rooms and facilities. When I’ve been, there have been a mixture of guys and you’ll no doubt see older gents. Have fun.