So, Welcome to VOIN, you're probably much like I was at the start of the game.

Lost and confused. Where does my gear go? What do I do with all these excess goodies I find?

The molten Cathedral is your first stop. Within which you can find a shop to buy new items, a way to get rid of old ones, the spot to cleanse "corruption" from an item to make it stick with you after death, and the Symbiosis Altar. Let me go through them one by one.

So where are they?
This part is pretty simple, from the entrance, jump through the anchors to end up on the main platform. The ominous green/blue orb in the middle, is the corruption cleanse. Use it, and everything corrupted and red in your inventory is cleared, and made to stay with you after death. Very handy.

Around this, is the store... Kind of. It may look like a set of things to buy for Ichor, but it's actually an upgrade for whatever is in each of your gear slots. If the weapon is the wrong one, take it out and sway it using F to cycle what one gets upgraded.

To the right you'll see a bunch of anchors again, if you don't use them, the little lowered platform is for "sacrificing". This is only useful if your weapon/accessory is Primeval or Firstborn. Anything else won't be strengthened. By dropping random items in the runic ring on the floor, you can sacrifice them to 'satiate' your chosen gear and boost it.

If you DO follow the second set of anchors, it'll lead you up to the Symbiosis altar. This only works for FULLY sated Primeval items, allowing you to sacrifice one, to boost another by transferring enchantments.

This is all I know so far, but I'll do my best to come back to this guide regularly to update it as I learn more!