Outlook add-in Office object is undefined - outlook-addin

Question

I'm having a really hard time trying to find any documentation for Outlook add-ins development.
I want to use the Office object to access the current message attachment files from within the add-in, but Office is always undefined.
I have the following block in my manifest, as it's shown on the website:
<OfficeApp
xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
xmlns:mailappor="http://schemas.microsoft.com/office/mailappversionoverrides/1.0"
xsi:type="MailApp">
And also the following line in my script before attempting to access the Office object:
<script src="https://appsforoffice.microsoft.com/lib/1/hosted/Office.js" type="text/javascript"></script>
My requirements are just
<Requirements>
<Sets>
<Set Name="Mailbox" MinVersion="1.1" />
</Sets>
</Requirements>
After just defining those the Office object seems to exist on the official site:
if ( Office.context.requirements.isSetSupported( RequirementSetName, VersionNumber ) )
What am I missing? I still get the undefined error for Office, and haven't found anything about how to make it work.
Thank you so so much in advance!

Answer 1

Per Office.js documentation ...
If you fail to include an Office.initialize event handler, your add-in may raise an error when it starts.
I believe the "Checking the load status" document will be great way to start.