Just got my RSK Mk3, how do I use this sheath?

Finally got an RSK Mk3, thrilled with the knife, confounded by the sheath. I think there is a belt loop in there, but what does all the other stuff do? Here's some photos, thank you!

My advice is to get creative.

I once asked Doug the same question. His response was that it was designed to work with several different attachment systems.

If attachment items get in the way you can always cut the related stitching and remove them.