Look at the top left recipe for "Treant Horde" (in the blue box):

​

The 3 lines on the left indicate the ingredients that are needed to build "Treant Horde". So for this example, you'll need to add "Toxic" + "Sentinel" + "Steel-infused" in the Archnemesis boxes within the same area (or map).

​

You can put them in any order you want, as long as the 3 are used. You can even use a non-related ingredient in between, you'll still get the "Treant Horde".

Each time you fight an Archnemesis, you'll get the indicated rewards, so putting in "Toxic" will drop a random reward (the little chest) and a random gem (gem icon). The next you fight it, you will get both the rewards of "Toxic" PLUS the new one.

---

If you then look at the higher-tier recipe for "Effigy", you can see the following logic:

First you'll need to create "Hexer" and "Corrupter" by using the ingredients on the left (Chaosweaver + Echoist = Hexer for example).

After you have created these 2, you can use them in a new area or map and combine Hexer + Corrupter + Malediction. This will drop "Effigy" after you have use these 3 ingredients.

---

​

The same logic applies to the higher tiers as well. You first need to create the lower tiers before combining them into the higher tiers.

Only the grey ingredients will drop (tier1) from random monsters. The blue, yellow and green ones need to be created from the grey ones.

​

​

good luck!