Cast on the required number of stitches as you would onto a straight knitting needle. Spread the stitches evenly across the circular knitting needle, being careful not to twist the stitches. Hold the circular knitting needle so that the working end of the yarn is on the right-hand tip. Place a stitch marker on the right-hand knitting needle tip to mark the beginning of the round. Knit the first stitch on the left-hand knitting needle tip. Keep knitting the stitches, sliding them along the circular knitting needle as you work them from left to right. When you reach the stitch marker, slip it to the right hand knitting needle tip a continue knitting around for the required number of rounds.