Slip stitching purlwise

I am somewhat new knitter. I know how to slip stitch purlwise but this pattern goes like this k1, sl3p, k1. My question is do I bring the yarn in front of neddle before I sl3p and then bring yarn back to knit next k1?

Welcome to the forum!
It may depend on the pattern you’re working. If the pattern wants the yarn in the front it usually specifies wyif (with yarn in front). If you pattern doesn’t say then you probably just slip the sts off the needle as you would for a purl stitch.
What is the name of your pattern? Can you give us a link to it?