First what are the dimensions of the land ? Slope faces what direction?
And what housing needs do you want to accommodate?

Start by considering how the home will be used. Block out spaces for a kitchen, a bathroom, and at least one bedroom. The maximum size of the house is dictated by the size of the land. In most places, the house cannot exceed 35% of the lot size. Also, consult a realtor because you want to be able to sell the house later and a funky house won't sell well.

Bedrooms must be at least 70 square feet and must have a window big enough for emergency egress. Check out NKBA website and learn minimum sizes of showers, bathtubs, etc. There are many code issues to consider as well. Sounds like you need an architect at least to get started.

Sudin, please tell us more about your needs. First of all, where are you located? It looks like all the buildings in the photo are square shaped, with additional stories here and there. Is there a reason they are all the same shape and is that what you are planning on building as well? How many people will live in the house? Do you want an open floor plan or more defined rooms?