Picking up Stitches

When a pattern instructs you to “pick up stitches”, does this mean to “pick up” the existing loops along the edge & knit from there (like I did for my Clogs)? OR Are you supposed to insert your needle through the outer loop edge & grap the working yarn to create a loop (like they instruct on Knitty Gritty? :?? Knitty Gritty also talked about only picking up 3 out of every 4 stitches of garter stitch, since it is wider than it is tall…

When you pick up stitches, you pull yarn through. The clogs were an unusual case where you picked up just the loop.

Usually the pattern tells you how many to pick up along a particular edge. Sometimes for things like front bands on a cardigan you pick up stitches in a ratio because of the difference in stitch size.