Thanks!
The decision to not put the explanation in game was my personal preference towards explaining as little as possible -- I wanted players to figure it out by themselves through the hints I provided esp. via the top left UI where the coins spin next to the counters too; and some of my test players did so without reading the desc. But looks like I need to keep in mind that it is not that easy to figure out XP
If I ever update this game I may explain it better; perhaps without words XP