Hello!
The button to interact with the building is spacebar, when you are at the tavern you will pick up a beer, and when at the tent you pick up a dwarf
If you have a dwarf, you can place him down where you'd like with spacebar again, and you can give a beer to a dwarf with spacebar when you are holding one!
I've re-taken a look at my tutorial and the section where it says this is a bit under informing, I'll definitely improve this should I update the game. Thank you for your feedback!
I hope you can give my game a second chance, thank you for playing! :)