At the most basic level, to run an AppleScript, just double-click it in the Finder like any other document.
Apple's Script Editor application will launch - it has a "Run Script" button in the toolbar; press that, and the script will run.
I'm guessing that most folks are going to be interested in the "Add an AppleScript to my OmniFocus toolbar and use it like a button" option, though.
To install any scripts you want to use this way, do the following:
- Create a folder named "OmniFocus" in the following location:
<your home folder>/Library/Scripts/Applications/
- Drop the scripts you want to access frequently into this folder.
- Quit and restart OmniFocus.
- Once OmniFocus re-opens, select "Customize Toolbar..." from the View menu. A new sheet will slide out of the topmost OmniFocus window.
- Alongside the various buttons we've provided for your toolbar, you'll see the scripts you placed in the OmniFocus folder in step 2. Drag the ones you want up into the toolbar.
- Once you've got the scripts positioned as you'd prefer, press the Done button to close the sheet.
(As an aside, if you change a script's icon in the Finder, the updated icon will be displayed here, as well. This is useful if you have multiple scripts installed and want to tell them apart without needing to read the labels.)
Does any of that help? If not, feel free to ask more questions and we can try to lend a hand.