Uploading Your App to Your Zendesk
Zendesk have an article on how to upload your private app to your Zendesk here: https://support.zendesk.com/hc/en-us/articles/203691246-Uploading-and-installing-your-private-app-in-Zendesk
First, create a Zip file of all your app files.
Go to your Zendesk, click on the Admin icon in the sidebar, and click Apps -> Manage.
Then click Upload App.
Enter the name of your app.
Click Choose File and select the desired file.
Then click Save, and agree to upload the app.
You will be prompted to install.
Once the process has completed, the app will be visible in the Manage Apps page on your Zendesk.
Now you are ready to use it in a ticket, click the Apps button in the top right hand corner and find the app to use it.