I'll try...
Point of View
First Person: When a story is told from an "I" point of view, with narrative being "I did this, I did that." There's still dialogue and everything, it's just that the narrator is also a character. You only get to know the internal thoughts of the one character...unless they're telepathic, I guess.
Second Person: People don't really use this anymore...but it's the "you" point of view. As in, "You do this, you do that." The only examples I know of are those Choose Your Own Adventure books. In this one, the thoughts and feelings are given to the reader.
Third Person, Limited: This is kind of like first person in that you only get the thoughts and feelings of one character (unless they're telepathic). Limited uses "he" and "she". This doesn't mean you can't use "I". You'd use it in dialogue, though, while exposition and narrative would be "he" and "she".
Third Person, Omniscent: This is kind of a "god" point of view where the reader can find out the thoughts of lots of different characters and can see all the characters and even see scenes that no other characters can see. It's the most open of the POVs. Once again, "he" and "she" are used in the narrative paragraphs.
Third Person, Objective: This is an unusually POV, I think. I haven't read any book using it, though I know there are some. This is what's used in an academic essay or newspaper article that's not supposed to have any opinion. The narrator will tell only exactly what happens and what is said. So there are no thoughts and feelings involved. This is the least personal of the POVs, I'd say.
Tenses
Past: Past tense is...well, in the past. Using the past tense of verbs. I went. He did it. She ate. They were going. We had read. That type of thing.
Present: This is present as in I go, he does it, she eats, they are going, we have read (that's present perfect I believe, which still counts as present, I think).
Future: I've never heard of a book written in future tense, but there might be one. This is I will go, he will do it, she will eat, they will be going, we will read. There's also will have read and sentences like that. Basically, future = will.
When you write a book you generally pick a POV and pick a tense...though you can switch around. Though you never change tense in the same section of narrative, really. Unless, of course, it's first person present and they tell a story in past tense... That's a little confusing. You might want to try writing a few short stories using one tense and one POV to get a hang of them and then branch out from there.
I hope I helped you some. If my explaination was terrible just tell me and I'll try again
