Once you've learned how to cast on a row, then you'll need to learn how to knit the row into something. The easiest way to do it is to use a knit stitch.
Time: 1 minute to hours, depending on the pattern.
Materials Knitting Needles
Insert the tip of the right-hand needle into the next stitch on the left-hand needle. You need to insert it from the left-side of the needle so that your needle is going from front to back of the knitting.
Hold the ball-end of the yarn down the back of the knitting, and then wrap the yarn around the right-hand needle with your right hand.
Pass the yarn under then over the point of the right-hand needle.
Gently pull the needle back through the first loop, and bring the yarn along with it. The left needle will now be sitting on top of the right one.
Slip the loop of the left-hand needle, so that it now sits on the right one.
Repeat! Multiple rows of knit stitch combine to make garter stitch. It's the simplest stitch. It forms a flat knit, and is perfect for scarfs and squares.