First of all hi to everyone and honestly I really am a newb

Ok I have read the forums and decided the adapter I'm getting is a 500mw Alfa Network AWUS036H with the possibility of adding a directional if needed.

Now I have been in touch with a supplier who answered some of my questions but this has me confused

Please remember that wifi is 2 way you may be able to see more
access points, but unless that access points can see you then the best antenna in the world will not help
Can anyone explain that in layman's terms. If the AP is throwing out a signal range of 200 mtrs and I can get 3 bars at 1000 mtrs with a directional then surely I can pull a connection. Or does this mean something else.

TIA