There is no hard rule in doing a garter tab cast on. It depends on the instructions given to you in your pattern. But for this part, you will learn the most common Garter Tab Cast On. To begin, cast on 3 stitches. Then, knit 6 rows. After knitting the 6 rows, you should have three ridges. These three ridges are your garter ridges. These are what you are going to work on next. Move or turn your work 90 degrees clockwise. Then, pick up one stitch in every ridge that you created. Insert your active needle into the edge of your garter ridge and knit through the stitch. Again, turn your work 90 degrees clockwise. Pick up 3 stitches on the edge. Once you have picked up these 3 stitches, you will now have 9 stitches. This is your Garter tab cast on. You may increase the number of your cast on stitches if you want to create a wider Garter stitch edge. All you need to do is add 2 rows of knitting in every extra cast on the stitch you make in step 1.