Ah garter stitch, the foundation of all knitting - thank you for all the work that you do! To work in garter stitch, all you do is simply knit every stitch in every row.

Take the needle in your right hand and insert it through the first stitch on the left needle.

Wrap the yarn around and pull the right needle towards you scooping up a new loop of yarn.

Slide the old loop off the left needle.

Keep repeating steps 2 to 4 to the end of the row. All of the stitches will be on the right needle.

Swap your needles over so the needle with the stitches on is back in your left hand, now repeat the whole row of knit stitches.