If writing in 1st Person of main character, how do you write in other characters if POV character can't see them, or hear them?
Question: If writing in 1st Person of main character, how do you write in other characters if the POV character can't see them, or hear them?
The short answer is that you can't.
1. Get really clever about finding ways for the main character to observe all the key events, or find out about them somehow (e.g. view recordings, eavesdrop, get second-hand accounts, read a newspaper, etc.). Lots of books do this (e.g. The Hunger Games
). At any rate, with a single POV character, the reader can only find out about events as the main character finds out about them.
2. Use multiple POV characters. Maybe you only need to introduce another POV character for one key scene -- a prologue, for instance. Or maybe you develop a subplot involving a second character that will weave throughout the book. Some books use half a dozen POV characters. Of course, the trade off is that the more POV characters you have, the less close a connection the reader will have with your main character.
3. Use an omniscient narrator instead. This lets you move around freely in the story world, but the cost may be that your reader does not feel an intimate connection with any one character. The reader's experience is one of looking at the characters rather than being one of the characters.
All of these options can work. You just have to decide which is best for your story and how you want the reader to experience it.
But don't underestimate the power of getting clever.
Best of luck.