Did you unzip them into the same folder?

Each installer is an executable. Each can be run by you manually.

The main installer asks, at the beginning, if you want to run all the sub-installers, or just do the minimal.

If you've only unzipped a subset, then you must tell it you only want to install a subset.

There are checkboxes for which ones to run. There is also a major choice to just do the minimal (no content) install. If all you have is the main program .exe installer, then you should not be trying to run the other ones that do not exist because you decided not to let them exist.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)