I just want back in your head...
First, you've got points of view. In a nutshell:
First person: I, we
Second person: you
Third person: he, she
Then you can have alternating POV's in the same story. And if your narrator is a character, he/she doesn't even have to be the protagonist, either. Yipes.
Next, you have to decide if the reader gets to know the internal thoughts of the narrator.
Is the narrator an actual character in the story? And is he/she reliable or unreliable? Oh, boy. You could even unfold the story via documents like letters or diary entries.
And of course if you choose a third person point of view, you must decide if the narrator will be objective (unbiased) or subjective--conveying the thoughts of the characters. If subjective, will it be limited where the narrator only knows what one character is thinking, or omniscient where he knows everyone's thoughts. Why not take it a step further...universal omniscient--the narrator knows things even the characters don't know. Um...
After you've sorted through that whole mess, you're not done. Oh no. Now choose your narrative time: past tense, present tense, or future tense.
Of course, this is all assuming you already know your target audience (MG, YA, Adult, etc.) and genre (sci-fi, romance, mystery, etc.) and that you've nailed that all elusive "voice" needed to make your book stand out.
But wait, are you sure you want to go with fiction to tell your story? Maybe you want to try non-fiction, poetry, a song, painting, or even *gasp* an interpretive dance.
Now even I'm confused. All I know is after trying out several different combinations, I'm very comfortable writing YA sci-fi novels told in first person present tense with a good cabbage patch or sprinkler dance move thrown in for good measure. Mostly kind of maybe for now.
What's your preferred narrative mode?