yeah i'm sorry there is no tutorial and I created the itch page too later.
The mechanic is that you have to change cards based on the value of the die, so you could not progress because the value of the die and the number of cards selected were not the same number. You can also pay coins to re-roll or change the die value, to select the number of cards you want.
As i said im late but now there is a quite clear How to play section.