For this platform group, you will need to select Mac OS X, Windows, or Linux. As you can see from the following screenshot, each operating system selection has its own set of options:

For Mac OS X, you will decide whether this is a development build or not. If it is, you will have the additional options of Autoconnect Profiler, Script Debugging, and Scripts Only Build. 

For Windows, you will select whether it is a 32-bit or 64-bit build and select whether you want to copy the PDB files. You will also decide whether this is a development build or not. If it is, you will have the additional options of Autoconnect Profiler, Script Debugging, and Scripts Only Build. 

For Linux, you will select whether it is a 32-bit, 64-bit, or Universal build. You will also decide whether this is a development build or not. If it is, you will have the additional options of Autoconnect Profiler, Script Debugging, and Scripts Only Build. Lastly, you will select whether your build will support Headless Mode.