First you need to know what subject, object, and possessive pronouns are.
A subject pronoun is the <em>subject </em>of a <em>verb,</em> also called an action. An example of a subject pronoun is shown on statement 8 of your attachment, "Stu gave"; "Stu" is the subject, and "gave" is the verb, or action, that he is doing. You know it is a subject pronoun because the subject, "Stu," is doing an action, "give." Stu is <em>giving</em>.
An object pronoun is the <em>object </em>of a <em>verb</em>. The object is what is being affected by the action of the verb. Statement 7 is an example of an object pronoun. "Hit" is the action, and "me" is the pronoun, because the action of the stone almost hit "me." So in <em>result </em>of the <em>action</em>, the pronoun was affected, rather than the <em>pronoun caused </em>the action.
A possessive pronoun explains what someone owns. An example includes statement 10. By the word "our" we are expressing ownership, because it is "our" brother.
I hope this made sense and that you can figure out the rest on your own. If you have any other questions, feel free to ask!