Place the pieces you want to join on top of each other, and line up the pieces.

Make a slip knot and place it onto your crochet hook.

Insert your hook through the front loop only of the first piece, then insert it through the back loop only of the second piece. Wrap the yarn around the hook and pull through all 3 loops on your hook.

Insert your hook through the front loop only of the next stitch on the first piece, then the back loop only of the next stitch on the second piece. Wrap the yarn around the hook and pull through all 3 loops on your hook.

Continue repeating step 4 to the end of your seam.

Cut the yarn and pull on the hook until the end pops through to secure the last stitch.