Next, you will be prompted to run the Facebook Messenger for Windows installer on your computer. You will see either a dialogue box
or a web browser alert asking if you either want to run or save the installation file, titled "FacebookMessengerSetup.exe." Click "Run" to begin installation without downloading the installer program or click "Save" to download the file directly to your PC if you intend to download Facebook Messenger for Windows later.
Click "Cancel" to exit the installation.
Once run, installation of Messenger for Windows can take a few minutes depending on computer and Internet speed. A dialogue box will appear, tracking the progress of adding the program to your computer.
After the instant messaging client is installed, Facebook will automatically log you in to Messenger and allow you to send and receive instant messages. Software updates will be installed automatically.