The last jump is the hardest. That should be no surprise. Only 1.4% of players are better than you, and there are some experts in that range. If not, there is always Lia playing almost optimal. I beat it only rarely. You play against those strong players all the time. The hand above is confusing for me. Clearly, you are sitting behind the spade suit and should make two or three trump tricks, plus the ♦ A. The bidding does not suggest a good fit either. So, I do not understand why most "Other Players" did not double. It went two down on my table. I am now playing Gavin Wolpert "Basic". There are some classes you can purchase on his page. The system is very expert oriented. But he is explaining it very well. Moreover, you will learn a lot about Bridge which can be used in other systems too. He is a great teacher. Unfortunately, a complete description of his system is not available other than buying and listening to dozens of hours of classes. There should be a book....