I'm no teacher, but... This is my explination of 1st person, 2nd person and 3rd person.
Example of someone speaking in 1st person:
"I went to the store and I bought a soda."
Anything with the word "I" in it is basically first person. This is a very popular usage in books....
Example of 2nd person:
"Mark is going to school to learn math."
Second person has no indication towards yourself, just to other people.
Another example:
"They walk to the bookstore. Mark smiles at John and John grins back."
Now, for 3rd person...
Thrid person is
rarely ever used in formal writing and
from what I've seen, it is used mostly in giving commands - "You
will do your chores" - etc. .
Thrid person is when you indicate what someone else is doing/has done/will do, without
mentioning their name, and without mentioning "I" (or yourself.)
Example:
"You go to the store. You buy a snack. Then, you go home. You had a fun day. Now it's time for you to go to bed."
OR
"You will do your homework or you will have a zero for a class grade."
Hope this help.