What to check before buying a html template - What should I watch out for?

Hello :) I want to buy a html template on themeforest. I´m a beginner in CSS and HTML. What should I watch out for?
These I thought about:

1. Check pagespeed of the preview? - Does it make sense?
2. Check how the code looks through inspect element/dev tools
3. Responsivness of the preview
   

I noticed the template I´d like to buy uses bootstrap which should be fine, hopefully I´ll learn it quickly.