Log in with the credentials provided to you and then select your Profile icon in the top right corner of the UI. From the dropdown menu, select Download Office Add-In.

In the pop-up window that appears, select Download.

Open Outlook and select Get Add-ins the Ribbon Bar.

In the next window, select My Add-Ins from the left side of the page.

Next, select Add a custom add-in, and select Add from file.

Find the XML file that you downloaded earlier and select Open to upload it.

Select Install in the notification window from Microsoft.

The Add-In is now included in your Outlook Ribbon bar, which is visible when an email is selected. You can access it by clicking on it.