K1b

I’m trying to make some slippers & came across k1b. Does anyone know how to do this? Thanks.

I [I]think[/I] it is referring to ‘knit 1 below’. You will find a video on this page:
http://www.knittinghelp.com/videos/knitting-glossary called k-b

That can mean two things - either k1 below or k 1 in the back of the stitch. For knit 1 below, you put your right needle into the st below the next one on your left needle and knit into it. There should be an explanation of terms used either at the beginning where the needle size is given, or at the end, or if it’s a book, somewhere in the book.