Assuming the sling is completely dismantled.
Take one end with 2 pairs of 2 holes, and a 5th hole at the end in it. Fold it thru the plastic, or metal keeper.
Fold the last 1" or so over double so the 1st, 4th & 5th holes line up.
The 2nd & 3rd holes should line up also, if this is folded right. One chicago screw goes thru 3 thicknesses of material, the other goes thru 2 thicknesses.
This is the butt end of the sling.
Pass the free end thru the rear sling swivel from rear to front.
Thread the free end thru the buckle you just attached to the end.
Pass the free end thru the front sling swivel from front to rear. Keep threading till about 2/3 of the length is passed thru the front swivel.
Take the loop (which may have a pull tab attached) & slip it onto the free end after it has passed thru the swivel. The tab should be on the inside, facing the stock.
Bring the free end back towards the butt end & thru the keeper again. It goes thru the keeper to make a "U" turn. If you've threaded it right the free end is now facing the muzzle again.
Line up the pair of holes at the end of the sling with the other pair in the middle. Depending on how much slack you left where the position of these holes will vary quite a bit. Dont worry as you'll fix this later.
One chicago screw goes thru in front of the slider with a tab & the other goes behind it. This is to stop the slider from moving when you adjust the sling.
Heres a check list to see if you rigged it right stage-by-stage.
At the butt end.
sling goes thru rear swivel, does a "U" turn & goues back thru the keeper. The chicago screws can't touch the stock because the other end of the strap goes between the heads & the stock.
At the front end.
the strap has a "U" turn thru the swivel. The "tab" is on the inside with the pull tab (if fitted) facing the rear, inside all sling parts.
In the middle. (Whever the middle ends up being)
From inside to outside, in this order.
Pull tab faces the rear.
Long sliding strap passes thru pull tab loop.
End of strap is held to outside strap with chicago screws.
Pull tab is in between the 2 screws.
End of strap facing muzzle is bolted to middle strap.
chicago screw heads face out, a way from stock.
If you haven't completely dismantled it, just read along & pick up where you need to.
Hope this helps.