Make sure you have downloaded ZENworks_Adaptive_Agent_Windows.exe to the target Windows device. If you have not, see Downloading the Module from a ZENworks Server.
Make sure the location of msiexec.exe on the target machine is in the path variable of the target machine.
At a command prompt, run ZENworks_Adaptive_Agent_Windows.exe to launch the installation program.
The installation program requires no user interaction. When it is finished, the Inventory-Only module is started and the device is added to the Inventoried devices page in ZENworks Control Center (tab > tab > or folder).