Hey, yeah i can see how it's a bit confusing. We didn't have a time for a tutorial.
So when you begin, the top-most row of dice represent the dices you have (they shuffle through their sides so you can recognise them), you can click on one to modify it. Then, on the lefthand side, you pick which face of the die you want to replace. The faces available to you are the other lower row of dices (ones which are not cycling through their sides).
After this you press exit and go on to the map where you can continue down a path.
Little red enemies are normal encounters
Big red enemies are elites
Coin is shop where you can buy faces
Meat is a resting place where you can heal up (small amount for free, more if you pay)
Door at the end is a boss.
Combat goes like this. Your five dices get shuffled, and you an option to roll one of two. You do this by dragging it to the center of the screen. You will then get three faces of that dice (the result of rolling it three times) and you have to choose two of the faces that you want to "play". After this your turn concludes and the enemy does his action.
Another dice then drops down from the tower.
When there are no more die in your dice tower all your dices get reshuffled.
Hope that clears it up, thank you very much for the comment!