Pretty much what Pete said. I then double check the tension by standing the bike upright, and squashing the rear suspension as much as possible (85kg of me on the topbox mount), to check it still has enough play in it. This is easier with an assistant
In theory you want the chain as tight as possible, but without any chance of it going tight as the suspension moves. The geometry of the Ten means the chain gets tighter on compression, which is why the manual specifies such a huge amount of slack when it's on the sidestand.