When do atrioventricular vales open and close?

In my head I thought atrioventricular valves open when there is a high pressure in the atrium and would close when there is a higher pressure in the ventricles to prevent back flow but that is the opposite to what it says in the above notes

Can anyone help?

That’s what I heard can you link the original website

I saw this on a website is the information correct as I can't seem to wrap my head around it
I do a level biology Aqa

Atrioventricular valve closed
- When pressure in atrium is higher than in ventricle→prevents backflow of blood from ventricle to atrium
- Atrioventricular valve open
- When pressure higher in ventricle than atrium→blood flows from ventricle to
atrium