Slip stitches

While most needle knitters say that slipping stitches are easy as pie, slip stitches on looms are even easier than pie - I have no other simile for that.

Slip with yarn in back (sl wyib)

This just means that you skip the stitch you are supposed to slip and then keep knitting.  The working yarn goes behind the peg.

Slip with yarn in front (sl wyif)

I transcribed the herringbone pattern using this, and found someone's youtube video doing this.  Instead of sl wyif, you take the loop off of the peg you are supposed to slip.  Take the working yarn and put it in front of your work, but behind the peg.  Put the loop back on your peg.  Your working yarn should be in front of your work, but behind your peg.

Slip as if to purl

Generally in needle knitting, to keep your stitches untwisted, you slip as if to purl.  This shouldn't concern a loom knitter, but sometimes people mention it in their designs.  Firstly, if you are transcribing a needle knitting pattern, this most likely will not concern you.  However, if slip as if to purl is mentioned for a loom knitting project, it would most likely be for slipping your stitch as you turn your knitting (back and forth, flat panel, single knit).  As you purl the last stitch, make sure the working yarn goes in between the last peg and previous peg.  It should not wrap around your last peg.

Slip as if to knit

As mentioned as above, this should not concern you unless it is about slipping a stitch to create a neat edge.  As you knit the last peg, just turn your work (you do not need to lift the loop off the peg like slip as if to purl), and knit in the opposite direction.