It took me a while to get it, but it eventually clicked and I got into the flow of things!
Generally the plan that worked for me is: pick up the card counterclockwise to your current, and advance clockwise twice. Pick the same as your current to open up blocked areas if needed.
Once the levels started having many guys I was worried that I also had to find a way to clear the entire board to win. Fortunately that's not the case, though that means the solutions for some of the levels are quite open ended. Though I could imagine this game having some very tricky puzzles with only one solution!
Also, today I learned about the four temperaments, that's quite interesting as a theme for a game!