Most packagers and setup developers have had that moment when they knew where a file needed to go, but weren't quite sure how to get it there. This is a Cheat Sheet for the translation between how the common folder paths resolve, and the variables you're most likely to need to map those values to in the installation.
Note that the behavior of InstallScript variables is somewhat more complex than this chart suggests, changing based on project type and other conditions on the operating system. I would recommend reading the individual documents when using these to ensure you are getting expected behavior.
Feel free to leave us suggestions for additional cheat sheets you'd like to see.