Slip stitches are also used within stitches themselves and to connect chain stitches to make loops. They’re usually abbreviated as “sl.st” or “sl st”, but sometimes as just “ss”.

First, put the hook into the next stitch.

Then yarn over and pull that loop through both the stitch and the loop on the hook.

Done, that’s seriously all you do.

For slip stitches (sl.sts) you’ll only need one chain and the beginning of a Row, kind of like a single crochet.

Like I said before, you can use slip stitches to join a chain and make a ring. Here I have 10 chs, and if I just sl.st into the first then I’ll have a ring!
You can also use them for joining in the round, another technique for crocheting in the round (one I don’t usually use)