Welp, I playing for long time and wonder how to upgrade or spend soul? thinggy I absore from zombie i killed. I think tutorial mention it is our own totem but I don't see anything in building menu. Also, Where can I find iron ore to craft iron pickaxe? I don't even see any furance or any kind of iron smithy tool yet. I try traveling around but keep hitting force field of "In development" i try to study lot of stuff but look like i still not unlock stuff to make wall/pole too. Look like that building need some sort of plank which i assume i need saw which no luck found it anywhere yet. Map also dont help at all soo suggest dev for GPS or something in future we can loot. (copy straight from Son of Forest i dont care or be like Stalker PDA mark stuff on map is better) There military camp and stuff but no high tech gear stuff is wild
To spend the "souls" you need to build up a Totem, and how do you build it?
First, you need a pencil that will make you able to "study" new stuff (how? simply on a campfire, burn some logs, collect che chorcoal and use it to craft the pencil)
When you get the pencil, you just need to Break a totem (the one around the map) and collect a "female" head, study it, and this will make you able to build the totem where you can spend and upgrade your character powers and resistences.
About the iron ore, there is a lot of "big chunk rocks" around the map, some are a little bit colored in brown (those drops clay) , others in gray/silver (those drops the iron ore) to break those you can use any pickaxe tool, even the one that use stone as a requirements.
When you get the iron ore, you need to smelt it, and this is where another building came in game, you can't miss it cuz it require 2 slaves to work xD.
About the saw, yes u need it to "cut" logs and get the wood to craft the building such as floor, and wall; it's located somewhere, but i wont spoiler too much

just look carefully, you wil find it

I hope it helped, Cheers <3