An Outlook add-in consists of two components: the XML add-in manifest and a web page supported by the JavaScript library for Office Add-ins (office.js). The manifest describes how the add-in integrates across Outlook clients. See Microsoft documentation for details.

Aurinko auto-generates an addin manifest for youe Aurinko addin apps, see how.

In Outlook (desktop) click the  Get add-ins ribbon button:

A popup will appear. Select  My add-ins, scroll down to the  Custom Addins section, and select the  Add from File... option. Upload the manifest file you downloaded from your Aurinko app, click Install.

The addin should be installed!

Close the popup and check the main ribbon menu in Outlook.

Click  Open Aurinko to open your Aurinko addin!