Hold the needle that has the cast-on stitches on it in your left hand. Hold the other needle in your right hand. Insert the right-hand needle (RHN) from front to back into the first stitch on the left-hand needle (LHN). Notice that the RHN is behind the LHN.
Form a loop by wrapping the yarn under and around the RHN.
With the RHN, carefully pull the loop through the stitch on the LHN so the loop is in front of the work. You have just made a new knit stitch, which is on the RHN.
With the new stitch securely on the RHN, slip the first or "old" knit stitch over and off the tip of the LHN. The knit stitch is complete. Notice that the stitch is smooth on the front and has a V shape.