The manual is not very clear on how to check the chain tension. I mean, at first glance this doesn’t look obvious, and if you don’t know that “link fork” means “swing arm” in KTM lingo, this is even more obtuse.
Also, to use this procedure, you need the rear lifted from the ground, from the swing arm with your favorite lifting gear. Using this procedure with a center stand or side stand will make the chain too loose or too tight!
It’s not that complicated once the process is understood: with the top portion of the chain taunt to begin with, you lift the lower chain in the position they indicate at the rear end of the B arrows, 2.5cms after the end of the slide. The gap (‘A’) needs to be 2-5mm between the swing arm and the chain (source).
There is another view of the same method, this one documented on a sticker affixed to the swingarm:
If in doubt prefer a loose chain. At rest on the side stand, the chain should be very slack.