I'm not going to give you all the answers because you need to practice using ser and estar yourself, but I will say that you should look up "difference between ser and estar spanishdict" on Google. I can't give you an exact link on here, so just look it up and it'll pop up for you. It was very helpful when I was learning Spanish myself because finding the difference between ser and estar was difficult at first for me too.
Let's look at the first question, for example. If you were to translate that first sentence, it would say the car ____ my brother's. Since the car belongs to their brother, it is a permanent thing, therefore you would use ser. To conjugate ser, you need to figure out of it's using the yo, tu (sorry there aren't any accents on here), el/ella/usted, nosotros/as, vosotros/as, or ellos/ellas/ustedes. Since the sentence refers to the person's brother and the car belongs to their brother, you would conjugate it to the el/ella/usted form. The conjugation for el/ella/usted is es, so therefore the blank would be es for that question.
Next, let's look at the twelfth question. If you were to translate that literally it would say I _____ studying for the exam. This is referring to time, which is not permanent. You're not always going to be studying for the exam, right? Hence the reason you would use estar. Once again, you need to figure out if you need to conjugate it to the yo, tu, etc. form. Since you would be talking about yourself here, you would conjugate it to the yo form, so you would say "Yo estoy".
