There are currently two ways that Gamemode 4 modules can be added to an existing Minecraft world: 1-click and schematics. You can also download a fresh world with the module pre-installed in it for most of the available modules.
If you get problems with installing a module, then post a message here so we can help you further.
1-Click Installation Edit
This method is the easiest for installing a Gamemode 4 module into an existing world, as you don't need any extra software to install it, and as long as you are opped, you can add modules to a server without even having to take the server down first! However, the 1-click will always install the module at bedrock level and will delete any blocks at its location, including other modules so it should be used with care.
To install a module using 1-Click, find the 1-click code on the Gamemode 4 website for the module you wish to install, copy it, paste it into a command block and power the command block. It is important that there is plenty of air above the command block in a 3 wide, three long pillar. For a full, detailed explanation describing the correct usage of 1-Click, watch the video below:If you want to turn a Homemade module in a 1-click look here.
MCEdit Schematic Installation Edit
Most Gamemode 4 modules have a schematic download that will allow you to import the module using MCEdit. Modules imported using this method may need to have their clocks manually restarted. It is recommended that you avoid importing the module so that it crosses a chunk boundary. You will need to install MCEdit on your computer to install a schematic file into your world. Using this method can have small changes, for instance, Lightning Rods have orange countdowns instead of white ones when imported via MCEdit.
World Download Edit
For some of the older Gamemode 4 modules, a world with the module pre-installed can be downloaded. This is no longer made due to lack of people using it, and the amount of time taken to make one, and some of the current world downloads may have modules that are not updated. If you wish to have a world download anyway, please request one on the forums and it will be considered.