Fusion forges lets you upgrade your existing decoration and get a higher "public order". Only 10x5 decoration items may be upgraded When you upgrade a decoration you increase its "fusion xp" when there is enough of "fusion xp" the "public order" of the item will increase. There are some materials/resources involved in this process.
Fusion basic materials
When you open the fusion screen, you will see at the top 3 parts:
1. Forge level — Determine the fusion process energy capacity, energy recharge time and the "fusion xp" you gain. It is recommended to increase the level as much as you can. You will need "decoration dust" which you can either earn as prizes in events, or buy them (using gold & silver pieces) at the "Master Blacksmith" (at your main castle).
2. Fusion energy — Every fusion process needs energy. energy recharge process takes time. Your maximum energy capacity and the recharge rate are determined by your "forge level".
3. Fusion coins — Every fusion process consume coins , which you can earn as prize in events.
How the fusion works
Every fusion process need 3 parts:
1. A "target" which is the decoration item that you want to upgrade You choose it by clicking on the middle.large box.
2. A "source" which is another decoration that will be lost after the fusion process.
3. A "catalyst" which is made of "decoration dust". You may assemble a catalyst from "decoration dust" or disassemble one back to dust. Every assemble/disassemble will cost you "fusion energy". There are levels 1-5 of "catalyst" (which you may assembe only levels 1-4).. Some high public order decorations will accept only level 4 or level 5 of catalyst. When you use a higher level of catalyst you get more bonus on "fusion xp", but higher level catalysts are not so easy to win, you will need to purchase them for rubbies.
Clicking on the smaller boxes on left/right will open a popup that will allow you to choose the "source" the "catalyst" (and also assemble/disassemble catalysts).
When you have chosen all 3, and you have enough "fusion coins" and "fusion energy" then you have two options to start the fusion: a "standard" process which will cost you "fusion coins" and a small amount of kingdom resources, or a "premium" process which will cost you rubies (both will need "fusion energy").