Player's Guide - Incarnum
This guide will cover how to bind Kruthik Claws as a Totemist and invest essential to get the acid damage.
Step 1: Rest. This should bring up the meldshaping menu above automatically. In this menu, select the meld you want to shape. We'll use Kruthik Claws (hit 3 then 2) shape the rest of your melds, this menu should then close.
Step 2a: This menu will automatically open after you have chosen your soulmelds. You must have a Chakra Bind slot unlocked (level 2 for Totemist to unlock the Totem Bind). Choose 3 for Kruthik Claws here.
Step 2b: this menu lets you choose which Chakra you are binding the meld chosen to. Totemists are special and get a "Totem" bind slot, choose this (press 1) here. This menu will close and you should see a message about your Primary Natural Weapon being equipped. You now have Kruthik Claws bound.
Step 3a: To get the acid damage, you need to invest essential into the Kruthik Claws. To do this, use the "Invest Essentia" option in your class radial, it looks like a Blue face with a third eye.
Step 3b: Choosing invest essential will open this conversation. First choose "Totemist Soulmelds", then choose Kruthik Claws and invest as much essential as you want to.
You now have acid damage at 1d4 per essential invested. Screenshot above has 2 essentia invests, so 2d4 acid damage.