Now that your frock looks somewhat like a hospital gown with no side seams, we are going to sew those up and make the kimono sleeves.
1-First you need to decide how large of an opening you want for your sleeves. Kimono sleeves usually have a larger opening to create a nice drape, so don't be too stingy. Use a straight pin to try it out and see what you like. I made mine 8" from the shoulder seam to the bottom of the opening.
2- Cut a piece of bias tape 2 times the length you determined (so it will cover the front and back of the opening) plus 2 inches for wiggle room. So, since I wanted a sleeve that was 8 " tall I cut a bias tape piece that was 18" long.
3- Place the edge of the armhole fabric inside of the center fold of the bias tape just as you did with the neckline. Pin in place.
4- Stitch in place by keeping the edge of the bias tape right along the right edge of the presserfoot and move the needle over to the left. The stitch should be at about 1/2". (this is the same as you did on the neckline). The end result should look like this:
5- Repeat for other armhole.
6- With right sides together, match up side seams and pin. Return needle to center position and stitch a 5/8" seam allowance along each side starting 1" above where the bias tape ends to the bottom of the frock.
7- Use pincking shears to clip edges of seam allowance and prevent fraying (optional) and then press seam open.
8- Continue to fold the 5/8" seam allowance at the arm hole where the bias tape is towards the inside of the garment. Pin and press. (you will not see the bias tape anymore on the outside of your frock)
9- Move needle to the left hand position. Turn garment to right side out (you will be stitching on the top of the fabric). Keep the fold along the right edge of the presser foot and beginning about 1/2" below the end of the opening stitch all the way up and round the armhole.
Once you make it back to the bottom, stop, pivot, and stitch straight across the bottom to meet back up where you started.
10- Repeat for the other arm opening.
Your frock probably looks like a potato sack right about now. No worries. I promise it will get better. Next time we will be adding a waistline.