Never mind, I solved it for myself. The instruction article is flawed: the option to add another email is in reality under Settings → Email Forwarding.
I’m glad you found the option, @Adam_G2! I’m sorry for any confusion! You can quickly provide feedback about this article to our content team in the “Was this article helpful?” option at the bottom of the article.
Let me know if you have any other questions! Have a nice day!