Help - SL2-p1-p2sso

hi ā€” I am having trouble figuring out how to do this stitch properly. Can any one explain it? The more detail the better as I am very simple when it comes to knitting direction.

Many many many thanks in advance.

It means you slip two stitches , together, from left to right needle, probably purl-wise, though Iā€™m always confused by this.
Then, you purl one stitch and you slip the previously slipped stitches together over the newly formed one.