Hey,
yes the rules are confusing at first, sorry if its not too clear yet. So in all games except the nullgame (which is a special case), the jacks are the highest trump cards. In the suit games, those where a player announces a color like clubs in the tutorial, the cards of those color are trumps as well and are ranked below the jacks. So in a case of a suit game of diamonds, all jacks are trump + all cards of diamond. You can check this also in the help section again.
Hope this helps
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