Help with Calibre

Hello

I am a total newbie to Calibre and to sites such as this one, is there a simple way in Calibre I can mark a book as already read, I have looked at some previous posts some of which refer to Prefixes but I don`t seem able to locate this within the preferences section.

Sorrty for taking up time with what is probably a basic item but I have spent a fair bit of time already on this and am not getting anywhere.

Thank You

SK