Then go to the in-client store by adding /inclientstore to the URL. Your link looks like this:
After a few moments the store opens. Navigate to My add-ins.
Click to add a new add-in.
Click to upload the manifest file.
Add the manifest file.
Install the add-in.
Refresh the page after installation. The 365 add-in should appear in your webmail fairly quickly. It can take up to 24 hours before the add-in is available in the local Outlook application.
