Your adventure begins in the cave you entered to seek refuge from the mountain lion.
 
The first thing to do is build a fire. Take the piece of hardwood and a bundle of firewood (on the ground near the cave entrance) and go to the remnants of an old fire in the centre of the cave. Close to the old fire you find some dry grass and a piece of softwood. Place the firewood and grass in the middle of the old fire and the piece of softwood on one of the rocks around it. Use the piece of hardwood on the softwood to create friction and re-kindle the fire.
 
 

SQUARES WALL PAINTING

 
Directly behind you is a wall painting of a 3X3 grid of squares, some of which are painted either black, red or brown. Click on the wall painting to see a flashback of meeting Klem. The signature stone he gave you will now be activated in your inventory. Note the resemblance between the squares on the painting and the markings on the stone. There's also a paint-stained 'combining rock' below the painting.
 
Time to do some cave exploring. You should find three piles (black. red and brown) of pigment powder, a small strap and some branches. There are a number of other wall paintings and a second 'combining rock' with three crude tools on it. For now, concentrate on the wall painting with the squares.
 
What if you used the three coloured pigments to duplicate the markings on the stone and the painting? Your problem is that the pigments cannot be used as powders, only in liquid form. Unfortunately there's no direct source of water in the cave, but there is something else you can use. Did you notice the icicle at the cave's entrance? Break off a piece of  ice and put it into the hollow shell next to the fire. Once the ice is melted, water can be added to the pigments. This must be done after you've put the three piles of powder on the stained 'combining rock'.
 
 

WALL PAINTING

SIGNATURE STONE

 
Squares numbered 1, 2, 5 and 8 remain as they are. Squares 4 and 6 are painted black, square 3 is painted red and squares 7 and 9 are painted brown. Once completed, the continuation of the Klem flashback is triggered, in which he talks about the drawings on the walls assisting you along the way.
 
 
 

HUNTING FRESCO

 
After completing the squares puzzle you can interact with the fresco of three hunters and a bison, painted on another wall in the cave. The hunters, their assegais and the bison are all 'clickable'. You need to find a way to get the hunters to kill the bison before it kills them.
 
The section on The Art of Hunting in the documentary database refers to "different launching techniques", which is a clue to solving the puzzle. The throwing technique of the two hunters with assegais is ineffective against the bison, but if you give one of the assegais to the hunter with a 'slingshot', the combined force does the trick. To do this, first click either assegai, then click the hunter on the left (while holding the assegai) and finally, click on the bison.
 
You now know what to do to get rid of the mountain lion.
 
 
 

MOUNTAIN LION

 
Oops! You accidentally dropped your assegai before fleeing into the cave. You have to chase the mountain lion away from the cave entrance in order to retrieve it. Animals are generally afraid of fire, so use your fire to light the branches you found and, when lit, throw them out at the cave entrance.
 
Exit the cave to retrieve your assegai and also take the deer antlers lying on the ground.
 
The graphic in the documentary database illustrates what a spearthrower looks like. The deer antlers have the same basic framework and can be modified to make a spearthrower. Place the antlers on the second 'combining rock' and use the tools to do this. Note that after picking up and replacing any one of the tools, a description of each tool will be displayed when the cursor hovers over it.
 

 
Use the knapped flint (middle) to cut away the three horns facing away from you at positions 2, 3 and 4 in the graphic. Next use the awl (right) to make holes at either end (1 and 5 in the graphic). The spearthrower needs to be refined by using the scraper (left) at position 3 in the graphic. Finally, attach the strap to the antlers and take your new weapon.
 
You can't use the spearthrower from inside the cave so collect and set alight another load of branches to again chase the lion away. Armed with your spearthrower you can now venture off in pursuit.