To use a newline in the result of find and replace, enable the Use Regex option and use "\n" in your replacement text.  For example, given this text:
hello, world, goodbye
If you'd like to replace the ", " with a newline so you end up with this text:
hello
world
goodbye
In the find and replace settings, enable Use Regex, enter ", " as the find text, and enter "\n" as the replace text:

Then click Find All and finally, click Replace All.