For some reason I cannot check Directly Edit BSA cause I cannot find it.
can anybody pls help me.

Er... I had to google that, and even then, I'm not quite sure what it is.

What is it? The "Directly Edit BSA" bit, that is, not Qarl's, by which I assume you mean Qarl's Texture Pack 3, or QTP3.

edit: Is it, or was it once upon a time, an option to do with Archive Invalidation, perhaps?

I have installed it but I do not get the Archive Invalidation part

Hm. Yeah, could be some outdated info re: Archive Invalidation. Simplest way to deal with it nowadays is via OBMM (Utilities -> Archive Invalidation -> Update Now; only needs to be done once, and should already be on BSA Redirection by default, which is where it should be, by the way) or Wrye Bash (right click on bar just above BAIN package list in the Installers section, and select BSA Redirection, if isn't already selected, which it probably will be anyway). Or, you can grab Archive Invalidation Invalidated from somewhere (e.g., tesnexus.com) if you really must.

Simple as that. No need to worry about other forms of "AI".

thanks