Place your stitches on circular needles or double-pointed needles. If using double-pointed needles, distribute them evenly (shown here on 3, but you can use 4 if you prefer).
Place the first stitch from the right needle onto the left needle (Stitch A).
Pull the first stitch from the left needle (Stitch B) over Stitch A onto the right needle. Your knitting will now be joined in the round.
Stitch A will the the first stitch of the row. Stitch B will the last stitch of the row. Knit normally.