Codex has quite a few useful tricks. For example, click Copy in the upper-right corner of a conversation, then select Copy deeplink. That gives you a conversation link. Paste it into a new conversation, and you can ask Codex to read the contents of the old one.
There are also Fork and Branch in new chat. Both create branches for exploring new possibilities. The difference is that Fork branches the entire conversation, while Branch in new chat lets you choose an earlier turn as the starting point.
This description may sound a little abstract. Try it once in the app and you’ll understand.