Here is the dress I was copying.
And the dress (minus hemming the bottom and the sleeves).
The rest of this post will be the details on the construction.
First sew the front to the back, right sides together.
Make the bias tape and attach it. If you choose to do the facing instead of bias tape, attach the interfacing to the facing pieces. Sew the facing to the right side of the top. Press the seam and understitch the facing.
I tried to use the bias tape foot, but it didn't work out.
So then I sewed on some flannel bias tape over the other, instead of removing the mess, which made my seam much bulkier than a single layer of rayon binding. If you need instructions on how to make bias tape, I can do a separate post on how I do that (which is a tad different than other methods).
Line up the top skirt layer with the top of the dress.
Draw seam lines for the sleeves that start at the edge of the skirt layer (in a disappearing marker or chalk line, not the permanent marker I used so that you could see it). I would come up about 1 1/2 inches (at least 5/8", but more is likely better on an adult dress). Then sew along that line.
Right sides together, sew the top skirt layer to the top using 5/8" seam.
Sew another line 1/4" from the edge. Leave an opening to insert the elastic.
Next, sew the bottom to skirt layers into tubes. Then at the top edge of each of the tubes, sew using a very long stitch two rows for gathering, one at a scant 5/8" and the other 1/8 inch closer to the edge.
Gather to fit the skirt layer above it and sew right sides together. For this I marked sections at 1/8 around on both parts and matched the marks.
Measure the length of 1/4" elastic that you need around for comfort. To insert the elastic easily, I like to attach a safety pin. Sew the elastic together and sew the seam shut.
The almost finished dress. To finish it, I would serge all the seams and possibly reinforce the sleeve seam with grosgrain ribbon and hem the sleeves and bottom. For the nerdlet, I intend to chop the sleeves because she is expressing dislike of the long sleeves already.
Let me know if anything was unclear or needs further details or any opinions you wish to share.