Asus Prime x570-Pro how to enter boot options?

I know it is a silly question but i cannot find the answer :)

Of course i know how to change the boot order in the BIOS or how to select a different device for the next boot from the BIOS.

But…

Asus Prime x570-Pro how to enter boot options?

Source: [H]ardOCP – Asus Prime x570-Pro how to enter boot options?