Q.how to grow dwarf haricot beans
I plant these every year and they never see the light of day. I have tried planting deeply, very shallow as have heard they like to see you leave, putting in pots and soaking on damp kitchen paper all to no avail. My neighbour has rows upon rows and they are up within 10 days of planting.

Here's some basics on growing green beans. https://www.gardeningknowhow.com/edible/vegetables/beans/tips-for-growing-beans.htm
Your dwarf haricots should require the same kind of care. A couple of questions come to mind; do you have good seed? Plenty of sun?
I think if I had a neighbor successfully growing something, I'd try to look over their shoulder, and pick their brains.