We are planning for old age. That means we want to have everything essential on one level. Upstairs is for the children and grandchildren when they come to visit, and hobby rooms, office, etc. The area above the living room is open. Downstairs it is important for us to have separated areas. Kitchen/dining and living room should not be an open, connected area. We often have visitors while others want to watch a movie in peace.
It is a good approach to start from your own wishes and needs. Write these down in more detail – don’t pay attention to whether something contradicts or not. Collect pictures of houses and details that you like. Here too, there doesn’t have to be a consistent logic. Describe which detail you like and why.
Then go to an architect, show them your materials and find out how eager they are to build for you. Choose the most motivated one and let them create a draft. Architecture is an art in itself. Your draft shows that you are far from mastery. It would be a shame about the money and quality of life in your own house, wouldn’t it?