The pattern I made is from this drawing
I always start with the cups, the important part is the volume, and that there is a gap at the centre front that needs to be accounted for. When you lay the cups touching at the middle point of the bust; the further away the pattern at each end the more volume is created. To work out where the curve of the wing sits,
To work out the width at the top then you have to know your strap width, then take into account seam allowance. The strap point is designed to go in line with the outer part of the nipple, as the outer part of the breast is the heaviest.
The side cup is designed to come right to the side of the body (where a side seam on outer wear would be). Putting the patterns together at the bottom ensures that the underband is a smooth curve, and also the curve across the bust. A vertical seam on a bra will be more up lifting than a horizontal seam.
Over lapping the cup patterns you can see the amount of volume that will occur. From making this pattern, next up will be making a toile for fits.