I am casting to my character in the EnemyHUD so that I can get his health but I don’t know what to use as the object.
Like a main boss’ HP? You have to get a reference to that actor first. You need a “GetAllActorsOf …BasicEnemy” for that, which gives you an array. If there is one enemy you can just “Get 0”, if not then you have to find it somehow which one is the selected. Then you don’t need casting, cause you already get the correct type, and you can ask it’s HP.
I feel like you are quite a beginner here, so I’d recommend checking out the official video tutorials, they are very good. If you make those games as they show, you’ll learn a lot about some basic elements of the games, and can help you start your own much more easily.