The tool is a simple spreadsheet to help software companies estimate effort required for software development projects and allocate time for the different activities involved in the software development lifecycle.
The basic assumption is that estimation at the task level happens for the coding hours involved in the task. Sum of all such hours will give the total coding hours involved in the project. The rest of the activities in the project lifecycle are calculated as percentages of these coding hours. For each activity different individuals would be involved and the percentage of time that each role has to spend on each activity would depend on the operational structure of the organization. Once the time to be spent by different roles are calculated these hours are then split up into hours that are to be spent by individuals who are added with the given roles into the project. The system also accommodates for different productivity levels for individuals with different levels of capabilities. The system also supports inclusion or exclusion of different types of activities based on the size of the project. This is to accommodate the possibility that smaller projects might not need some steps in the SDLC or might only require higher level activities.
You can see instructions for using the system in the wiki