Use the sizing paramter that is available to you. There are two options: functional points and lines of code.
If you chose functional points, you have to input it and the programming language used.
If your chose lines of code, you have to input the lines of code for your project.
Under basic COCOMO, there are no cost driver inputs required for COCOMO estimates.
However, with intermediate COCOMO, there are multivariate cost drivers which help to make better COCOMO estimates.
They are not missing. Under intermediate COCOMO, some cost drivers have different ranges.
No, you have to press the calculate button everytime you change your inputs.
The total amount of person-months estimated for your project.
The total time estimated to finish your project based on person-months and estimated required staffing.