Rich Snippet / Event Markup error from Google Search Console team

Hi all -

Google Search console reached out by email to kindly tell me that one of my sites is affected by 39 instances of "Event markup issues". Opening the Events report in webmaster tools, I am confronted with this:

If I look at an individual url within Google's structured data testing tool, I see this, telling me location and start date are missing (odd immediate spike in data from mid August...?):

Now, I don't know code, but I am surprised to see lots of other posts talking about schema.org and the need to add code for things like this (similar problems occur for blog posts apparently).

Given that my events have locations in the "Locations" tab within each event, what exactly am I supposed to do to get the data correctly listed with Google? Surely I shouldn't have to learn some code and add it somewhere? That's a bit 2013...

I could be adding locations incorrectly of course, and if there is a special way to add locations I would be grateful if anyone could share how to add them "correctly", else is there anything else I can do to get things correctly listed? Same for start date...

What am I missing and how to do I sort it out?

Thanks all