You have to run the setup file, of course, and install the update in the same folder as your previous version.
However, I'm not sure if the Sybex version supports updates. If you can, I suggest you return the product to your supermarket and buy A8 Extra or A7 from a user here in the forum (via license transfer).

How much is A8 Extra second hand?

I guess you could stick to the free version of A8, as the only thing it does not support is the ability to load DLLs. (And you always have a logo in one corner)

As long as you do not want to publish or need shaders/DLLs, I would not recommend to buy A7/A8.

I just upgraded to commercial but in this case I think I cannot sell the extra licence
and A8 is really better!

A8 Extra from Sybex supports official updates. I use it und updated.

WOW
I downloaded the 70 MB and update
lot better now
and the shadow map resolution slider
cool