I played Euchre once in the Army, with guys from Montana, South Dakota and Minnesota. I didn't understand a thing. Spades were trumps. I had A, both bowers, K and Q of Spades. They never let me play again.
I always thought card games had 52 cards (plus sometimes jokers) until I learned pinochle and euchre - euchre uses the pinochle deck without the duplicates.
Sorry to take so long to reply. If you are leading out and do not have a trump card, You could lead high or low, but you would hopefully have paid attention to what was played before. For me personally, I am always leading high, unless I am trying to get a player to use a trump card so that I can be assured my non trump high card will go through on another turn. Hope that makes sense.