@Jeff Yang - @Scott Seaman
Scott is correct that you should determine if your site will be on a septic system which will limit the buildable area of your lot.
I work as a Civil Engineer in the Development Services Department in Colorado Springs and I recommend that you contact this department in your area.
Here in my department the process starts with our planners which cover zoning and will determine the type and quantity of structures you can build. After this is determined the application will be run through our engineering department where we cover traffic/access and drainage improvements, then the health department to determine if you have the proper water and wastewater services. There are many reports that must be submitted to these department which include:
Preliminary/Final Drainage Report, Erosion Control & Grading Plan, Water Report, Traffic Study and an Erosion Control Permit will be required if the area of disturbance is greater than 1 acre, which @J Scott mentioned.
If all is good, the project would be taken to the Planning Commission which is technically a public hearing. If nobody is opposed to the project this will likely be a consent item meaning the PC members just okay it without further discussion and the project moves onto the final hearing with our Board of County Commissioners.
Once the project is approved a final plat will be recorded if you are subdividing lots. You would be dealing directly with the Building Department from this point on to obtain your building permit.
I'm oversimplifying the process but those are the general steps. There are many submittal fees that are required with this process that can easily add up to $5,000 or more here in Colorado Springs.