CloudSim is a toolkit (library) for simulation of Cloud computing scenarios. It provides basic classes for describing data centers, virtual machines, applications, users, computational resources, and policies for management of diverse parts of the system (e.g., scheduling and provisioning).
These components can be put together for users to evaluate new strategies in utilization of Clouds (policies, scheduling algorithms, mapping and load balancing policies, etc). It can also be used to evaluate efficiency of strategies from different perspectives, from cost/profit to speed up of application execution time. It also supports evaluation of Green IT policies.
The above are some common scenarios we envisioned and that users have been explored. Nevertheless, there is no limit on the utilization you can make from it: classes can be extended or replaced, new policies can be added and new scenarios for utilization can be coded. Think of it as the building blocks for your own simulated Cloud environment.
Therefore, CloudSim is not a ready-to-use solution were you set parameters and collect results for use in your project. Being a library, CloudSim requires that you write a Java program using its components to compose the desired scenario. Nevertheless, CloudSim can be used to build such a ready-to-use solution.