Install guide
Windows
For windows you have 4 options.
32 or 64 bit
Technically you only have 2, as you either have a 32 or 64 bit computer.
To determine which category you fall into, use the search function from the start menu to look for "system information" and open it. Find System Type. This tell you if your system is a x32 or x64 based system.
Installer or Zip-Package
This part is up to you. If you want install factorio like you would any other game from a disk or download, then get the EXE installer for your given system.
Otherwise, you can choose to get the zip package, which you can extract normally, and then play the game straight from that folder. This can also be copied to any USB device and be played from there.
Or it is also useful for modders, to have several installations of the game to test things working.
MacOS
TODO
Linux
TODO