FOSS gamedev and creative worlds

Help please

Hmm.. you don't just install them.
You download the code and compile it.

You can, however, install Mods.
That's the main reason C55 introduced Mods, so just about anyone could install them.

If you need help with either of those, it will help to at least know what Operating Systen you use and which version are you currently playing.
(be warned though: if you've never compiled anything before, it might be quite daunting)