Reply To: The "Create New Topic" form is your friend.

Example 4
This is what it looks like if I click “reply” to reply to Example 1

Note that “nested” (indented) replies will only move one step over to the right. With more levels of nesting, the words would get so squished, that it’s very difficult to read on some mobile platforms. So keep using reply. It’s still working its magic even if you don’t see an extra indent.