SliZeD

I don't understand, everybody is talking about the flush thing.. But I don't have a numpad because I am playing on a gaming PC. What can I do then? I change the zoom in & zoom out and zoom in(toggle) & zoom out(toggle) from + and - on the numpad(i don't have numpad) to arrow button up, and arrow button down, I don't understand what this flush method is, can someone please help me and tell me what to do when I do not have a numpad? :) -SliZeD