vi has an option that lets you
define a right margin and provides a carriage return
automatically when you reach it. For right now,
while you are inserting text, press
RETURN
to break the lines.
Sometimes you don't know whether you are in insert mode or command mode.
Whenever vi does not respond as you expect, press
ESC
once or twice to check which mode you are in.
When you hear the beep, you are in command mode.