OpenTerrainGenerator is a mod which modifies the default world generation of minecraft.
You are either able to modify the world generation like you want or you can use a world preset.
First you have to switch your server to the forge server software.
Afterwards go to the worlds page and click the generate Button:
Enter the name of the preset, in our case "Biome Bundle", into the name field and "OTG" into the worldtype field.
Complete the process by clicking the generate button. Please note that your current world will be deleted.
As last step you only need to start your server.
Please note that you need to install forge, the OTG mod and your world preset mod on the client too.