London: How to enable memberships and subscriptions?

Hi there, I’m a brand new Ghost(Pro) user and have virtually no coding skills in any language (I was proud of myself for managing to change some text in the Lyra html signup form, if that gives you an idea of my skill level). But I really, really love the London theme and would be thrilled if I could learn how to make it work for a subscription newsletter instead of Lyra. How hard would that conversion be? Is there a good guide somewhere that breaks the process down in terms I might have a hope of understanding? Thanks for any advice you can offer, even if that advice is “don’t bother.”

edit: Thanks to this thread I’ve learned that I can get at least part of the way there by copying Lyra’s /members folder and routes.yaml into the London theme. Looks like the main issue after that is copying some css as well to make everything show up in the right places. How would I know which css to grab from where, or is it easier to make the imported Lyra files conform to London’s existing css instead?