Okay. I will recommend you two plugins. Voxel Sniper and World Edit. You need a server for both. You can create a server easily.
Once you have both plugins, get your arrow in your hotbar and do this:
- Use the command /v [material ID] to select the material you want
- Use the command /b [radius] put on the radius how big you want corn to be. For example: 20.
- Use the command /b s and with the arrow click on the block where you want corn to be centered. will color the floor into a circle from the selected material.
- Now in the middle you want to put 8 chests. 4 every half of the circle in the middle and the other 4 in the corners. then just trace it and make the pedestals. Will have an 8 persons corn. on every 1 of those 8 pedestals 2 must go there. Just put 2 pedestals on every open space in the circle and will create cornucopia. then you can add other more elaborated stuff.
Thats how I did mine. Took me 5 minutes to do it.