they are completely different slings. use the one on the right (i'm pretty sure it's the spectre gear, formerly CQB solutions, even though you said it was on the left in the picture)
the funky end goes up front. take the very short tab and run it through the sling mount on the front of your rifle and velcro it down. then take the longer portion that runs perpendicular to the main sling loop and wrap it all the way around your barrel/handguards.
cqb sells two models, one for the small old handguards and and oversized one for folks who put quad rails or the larger handguards. so if it won't wrap all the way around, send it back, or use the blackhawk.
you can find detailed installation instructions on their website.
finally, take the loop that's still hanging and put an uncle mike's quick detach loop through it and stick it on your stock.
If you enjoyed reading about "Please help me! I feel like a huge idiot!" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!