The CoApp installers follow a certain naming convention. The names that contain the string "win7" install versions of the CoApp that contain code making them compatible with Windows 7 but they run on newer versions of Windows as well. The other ones do not run on Windows 7, only newer versions of Windows. I think there is better usage of system features in the CoApp versions destined for newer versions of Windows.
The CoApp installers with "_64" in their names are for 64-bit systems. The others are for 32-bit systems. Pick the one appropriate for your system.