How to do you set a Zoom Webinar to start at 11:15am?

@TMCharity,

It is possible to schedule in 15 minute intervals. This must be manually typed in the box rather than chosen from a drop-down. Include the colon when typing and hit enter when done and the time should save.

Photo attached. 

If still having trouble, you can save for 11, then manually move the webinar time on your calendar to 11:15. Once it's saved, then proceed to add your attendees. 

Hope this helps. If this answers your question, please accept as solution.