How to set out foundation on steep slope?

For the construction of the foundation, many factors are considered. Type of soil, slopes, drainage of subgrade, structural loads etc.

For the construction on steep slopes, make a structural drawing from a localised structural engineer. that person gives you a better idea for. Constructing a foundation for your land by analysing the type of soil and water table level. The civil engineer also takes care of all the local government regulations.

As you ask in a question, the architect only designs the outer surface and interior of a building, but not the structural design, foundation plan or construction plan.

There are two ways to set out foundation on a steep slope :- 

1. Cut and fill refers to the process of leveling out the ground for the foundation by adding soil, removing it, or both. Soil may be brought in to fill the plot and make it level, or it can be dug (cut) from the slope and either trucked out or used to shore up retaining walls for the home. Depending on the grade, soil conditions, and other factors, cutting and filling can make construction multiple time more expensive than that for a home on a flat site. 

2. Using stilts is an alternative to cutting into the slope that involves using a crane to lift the home onto supporting wood or steel columns. This can be a much more cost-effective method than cut and fill and can also open up the realm of possibilities for home replacement such as building out water over trees or water.

i think you can try the cut and fill method and then the area will be flat, for the filled are compact harder and harder also from the cut region for stability or otherwise design a house in a storey manner.

Architects are not structural designers. They design mostly the looks of the building and inner space of the building. Get your building designed by a qualified structural engineer. He will provide you actual construction drawing which will have all the details of the foundation and other structural members. It will be easy to understand the construction drawing.