Set up custom domain email in Microsoft Outlook , not Go Daddy

I have a website hosted with www.50webs.com. I would like to use a custom domain email address via Outlook ( send-as custom domain). I need you to help me create a video on how to do this. I will create a test email address for you to use and you can log into my outlook account. This will be for outlook live and outlook app ( are they the same?)

I am not able to follow these instruction:
https://cp.50webs.com/help/view-article/?id=435

Those instructions are for outlook regular, not outlook live. need both.