Send HTML email in Outlook 2016

I have created a HTML page with modified from a template I got.... I want to send as a HTML based newsletter in Outlook 2016.

However the guides I see as "insert as text" do not apply to Outlook 2016 as there is no dropdown for inserting files for that in the 2016 version.

I am wondering how I go about being able to send this HTML email? Many thanks.

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