Thanks for playing! It's definitely not you, it's a little overcomplicated. Basically, when you look at a signal it changes color according to the category of signal (friendly/diplomatic/hostile), and any response from the right category will buy you some time. But you'll need to scan to read the message and figure out the precise response. Get a greeting, send a greeting back. A response from the wrong category will get you a strike.
As is tradition I spent way too much jam time on the art and had to hastily string together some sort of game before the deadline :' )