Portal for one specific newsletter

Hello, my organization has three different newsletters for three different products, and we would like to send partners a link to sign up for one specific newsletter (not to a portal to sign up for all three newsletters). How can I do that?

Don’t use portal. Use a custom sign up form on a page, and link to that page. This should get you started:

Ah thank you! Do you know if there are examples of ready-made forms to use? I’m trying to follow the dev docs but it’s above my technical capacity

I found this embeddable form which would work great, if there is a way of using for one specific newsletter:

<div style="height: 40vmin;min-height: 360px"><script src="https://cdn.jsdelivr.net/ghost/signup-form@~0.3/umd/signup-form.min.js" data-background-color="#08090c" data-text-color="#FFFFFF" data-button-color="#f19935" data-button-text-color="#FFFFFF" data-title="Shira newsletter" data-description="Updates on new features and improvements in Shira, what's next, and user stories." data-icon="https://blog.website.com/content/images/size/w192h192/size/w256h256/2023/07/Logo_White-text.png" data-site="https://blog.website.com/" data-locale="en" async></script></div>