Make sure that the Action has a .fwaction extension prior to installation.
To install a new Action, most of the time you can just simply double-click on the Action file itself. This will prompt a message alerting you to the fact that you're installing an Action - just click OK.
With some Actions the above method may not work, in which case just drop the Action on to
the Freeway application icon either in the Dock or in the Applications folder, or choose "Install Actions" from the
Edit/Actions menu from within Freeway.
The Action will be copied to your User/Library/Application Support/Freeway/Actions folder. Note that this is not the Library folder that you can see by opening your hard disk icon on the Desktop - Actions are stored in the Library folder within your User folder. To access this folder, type Shift-Command-g then enter (or paste) the following in the Go To Folder dialog:
~/Library/Application Support/Freeway 5/
~/Library/Application Support/Freeway Express 5/
Click "Go" and then open the Actions folder.
Users of earlier versions of Freeway should change the version number accordingly.
Note that the "tilde" character (~) is generated by holding down the Shift key and typing the "grave accent" key (immediately to the left of the "z" key on a standard Apple keyboard.