You will often want characters to talk to each other in your stories, and you will want the reader to be clear about which character is saying what!

Every time a new character speaks, begin a new paragraph.  If two characters are talking back and forth, then you will need to create a brand new paragraph each time the speaker changes!

If this seems confusing, open a book that you like and look for pages that have speech on them.  Study the way the author separates the lines of speech.