Here are the two pictures:
Then like in Mucha's style I had to find a lady which came from a stock photograph.
So from there I could start to paint. First I had to buy the proper canvas size which ended up being a 10 X 20 in canvas. I painted a fast sketch on the canvas with yellow color like so:
Fortunately, the paint I had applied was not too thick and dried quite fast. Already the next day I could continue on painting. I did a lot for a second step, and will probably have to work much harder to fix little details I find irritating such as the top not being a perfect half cercle. The color of the dress needs to be fixed up to match the background better. The entire top symetry needs work. For now this is what came out of the first few hours of work.