First one, you have two points to remember. That's it. Two. Done. The first one is the structure. You have to remember and know how the grammar is made. Okay? The second point is how or why do we use this? Why do I need to learn this stupid grammar? Am I ever going to use it in real life? Why would I say this? Why do I need present perfect? Why can't I just use simple past? Why do I need continuous? Why do I need passive? These are the questions you have to ask two people, one, your teacher, and two, yourself. If you are teaching English and you don't know structure, and more importantly, how and why, you've got some homework to do.