My head is burning 🔥😅😅 I need help with automation.

What I want to do in automation is that my automation sends one of the 50 texts randomly. When the user comes back here, the last sent text should not be sent again. Instead, one of the remaining 49 should be sent. This should continue until all 50 texts are sent. Once all 50 are sent, it should reset and start over. How can I do this?