Some mechanics are a bit hard to find. Problem 1 I did find as well, don't know if that depends on stats or something.
The other problems are solvable, you just have to find where to click:
- To capture prey, you need to click on a defeated enemy in battle. The game will show you options what to do with em now. You can capture them, but they also can be devoured for health regen and hunger reduction, you can breed them on the spot, etc.
- Capturing slaves will give you the option to inspect them in their cages. There you'll find the option to brew stuff, since potions in this game need slaves as ingredients. This'll lead you to a minigame where you need to do certain things and add certain ingredients to make certain potions
Hope this helps you enjoy the game a little more