I had a hard time on the first 4 or so
After you have figured out a few, you start to get the hang of it and it gets a little easier. When I started I had no idea about how it worked or what the gist of the game was.
Of the first four, the first one was pretty hard, the second is very simple, the third is really tricky and the forth is so-so. Get through those (if you haven't done so already) and you should start to get the hang of it.