Two installations in one installer: Main app and host environment

[Motti]

On the NSIS Sourceforge site, there is this sample script for installing two software packages in one installer. I am trying to adapt it for my purpose, which is to install additional, ancillary software in a separate folder from the main install if the target machine is a Windows 32 system.

I am a newbie on NSIS and I'm having trouble understanding how that script works. Could someone publish a simpler, cut-down version of it, that -

- uses the older, simpler, non-MUI installer,
and is without -
- language selection
- the pages for the user to select components of the package to install
- the section below the comment "Please don't modify below here unless ..."

I am hoping that such a cut-down, simpler version will make it easier to understand and adapt it.