In high school, college or universities. Most studies of a subject lasts a year, and is divided in two semesters. In every semester you have test after completed some curriculum. Sometimes you are graded in the test. Other times you have certain assignments. All the tests and assignments all together, decide your grade for that semester. And after completed both semester for a year, the grades for the two semesters, decide your grade for the entire year you had that subject. In other words. We are taught certain subjects, and we are tested in them and graded in the end.
If we use this example and try to compare it with being a muslim. In your start of you being a muslim child, we learn the assignments, like 5 daily prayers, treatment of kin and friends, manners, conduct, character etc. We are prepared before our responsability will be put on our shoulders. After puberty, we are responsible for reading the 5 salah, and try to live according to all guidelines we were taught in our earlier years. And increase our knowledge and practice of our deen. After adulthood, we will be tested, by Allah in being given blessings, and blessings taken away, to see if we follow Him (Allah). As we make our choices, we are graded in some tests or just passed in others. After our death, we are questioned and our grades are rughly scanned. If the deed of salah, is graded good, our questioning will be easier. If we pass the tests of the grave, the tests of the day of Judgement will be easier. If we fail in the tests of the grave, the test of the day of judgement will be worse. Our final grade, will be given on judgement day, for everything we have done, all our life. That day our deeds will be thorougly scanned and weighed. And Allah will give full justice. If we pass that day, we will be given eternal paradise, with only happiness, joy, laughter and good things. And if we fail that day, we will be tested in hellfire and given paradise, some time later if we have some eman (faith) in our hearts.
In other words. All these actions we do everyday, that Islam has made obligatory on every of believers, are graded. And what happens to us for eternity is a sum of how obediently we have fulfilled our obligations towards our self and those we are responsible for. In other words, our life, our islam, is our test. And we need to pass it. If we want to live happy and joyful for eternity. May Allah make it easy for us to pass, all of these tests. Aameen.