Sewing two edges together

Sorry if this seems like the most obvious question ever, but I need to sew two edges together on my wool soaker. The edges are made up of 15 rows of loose purling (I think! I was ribbing there) and 15 stitches in garter stitch. I couldn’t find any videos for this, and have done one side but it looks really messy!

Are there different methods for stitching different types of stitches? How would I best go about it?

Thank u :muah:

Here is a pretty good link that may help you. I’m not sure what to tell about the loose purl stitches along the edges. but you might want to try some of the ideas here, and see how your work looks.