To create new action click the Action list manager at the app's menu.
Than just press the plus button and type any AppleScript you want. You can use Google to find AppleScript samples. For example let find the script which turn off iTunes playing. Just search for "AppleScript pause iTunes". The first search result bring us a next script:
tell application "iTunes" pause end tell
Just copy that script to the script field of app's new action. Than type a title for the new script. Let it be "Stop music".
The last thing we need to do is click the Save button. It's bring the save dialog window to you screen. Make sure that the place to save is "com.mamizhevapro.Max-Vecheslavov.Tiny-Counter" (it's a default AppleScript folder of the app).