In this form you can indicate which GEX extension packages must be
used in the game you are making. On the left there is the list of
Used packages and on the right is the list of
Available packages, and to move a package from one list to
the other, simply select it and press the button between the lists.
When selecting a package a short description is usually given at
the bottom (but not always if the package has been made by third
party developers), and further help may also be available by
pressing the Help button.To install new GEX packages or uninstall existing GEX packages, press the Install button and the following window will open:
You can see a list of all extension packages available (these are
stored by default in the "Extensions" folder of the root directory
where you have GameMaker: Studio installed). By selecting a
package and clicking the Uninstall button the package is
removed from the system, and pressing install will open a standard
load file window where you can select a new package from your
computer to make available within GameMaker: Studio.