There are several sets of instructions at that link and you didn't say which one you followed. The instructions for a single search head put the app only on that search head. You'll have to repeat the steps for the other SH (unless they're clustered or under a deployment server, but neither was mentioned so I'll assume they don't apply).
Don't forget to install the add-on on your indexers. That's also a separate step.
If this reply helps you, Karma would be appreciated.