CTA for newsletter signup

I currently send a weekly newsletter, curating posts and manually pushing it out. I’d like to split into three newsletters (the old one + two new ones) as the covered topics are wide enough to warrant separate readers and newsletters.

What I’d like to do is add two links in the current newsletter for the two new ones, so registered users or new users could sign up for that. How do I go about finding the signup link to each of the two new newsletters I’ve created in Ghost?