This repo is excellent. https://github.com/cloudflare/templates/blob/main/to-do-list-kv-template/app/to-do-manager.ts
My only issue is that this code creates one key for all the values and stores the values as one big array. I don't find that scaleable. I prefer for each key to have a separate value, and then use the metadata features of cloudflare kv to manage everything for list operations.
The only issue with doing it with separate kv is that that you are limited to 1000 keys on a list operation in cloudflare. But, if you need more than 1000 you can always iterate thru to get more.