What advice would you give on building muscular strength and stamina?

Great question, they are actually two really different things, strength and endurance.
Strength is often built beat through lifting heavier weight/using greater resistance, endurance is often built with repetition.
The two work some at odds with eachother, and good training requires balance.
Don’t overlook the run portion of the test either, running, especially with an emphasis on 30-60/60-120 sprints for speed improvement on a two mile test (yes I know that sounds counter-intuitive, but trust me, 17 years Army, Master Fitness Trainer).
If you want specific help building a plan, feel free to add/message me.

I took the test with no preparation and scored a 560. This test is not really one of strength but of muscular endurance. The only strength event is the deadlift. Everything else can be achieved with endurance and technique. That being said, for the deadlift, deadlift more. Work your quads and glutes. For the ball toss, it’s all technique. Do kettle bell swings to improve, and PRACTICE angles. For the hand release pushups, do close grip bench press and work your triceps. Start don’t close hand pushups as well. For the leg tuck, it is more of a back and arm work than abs. Strong abs will help, but if you can’t pull yourself up you won’t succeed. For the sprit drag carry lunges are great. It’s an endurance exercise so sprints sprints sprints. The 2 mile is the2 mile. But after 5 other events it’s pretty tough. Work sprints again. For all your workouts i would focus on high volume rather than high weight. With the exception of the deadlift.