Hi Georgia,
Thanks for reaching out to us!
The least I can say is that you are on the right track 😉
Once you are in the single-event.php file, you way place the div containing your featured image (.tribe-events-event-image) just underneath your main div (.type-tribe_events). Then you can create a div which would include all the other content (title, description, etc.).
From there on, it’s purely css (you can use flexbox or some older methods such as float or display:inline-block to achieve your goal.
Let me know how it goes,
Cheers,
Jeremy