Two installers, download and run...

ok, i'm very, very new at nsis and actually i don't understand nsis scripts yet 😉 (i can only make simple installers...)
this is my prob:
i have two installers (lets call them A and B) in A installer are files for my application and in B installer are "run-time" files for my own help system. When someone start installer A it should check for 3-4 files in sys dir, and if don't find them then installer should ask user does he want to download those files, and if he answer Yes then to download installer B and run it. after B is done then A continues install process..

i beleve this is very easy to make, but, as i sad, i'm begginer.
please give me some tips.

thanx in advance.

1. Use IfFileExists to check if files exist.
2. Use the InetLoad plugin to download files (you'll find a topic on here).
3. Use Exec to run the downloaded installer.

-Stu

thanx will see what i can do