OK, go through the process of making the Pack, then on the LAST screen that comes up (shown here), click on Copy Link, then go to add a "normal" post and just paste that link in.

Do I attach the starter pack to every post I want to mass tag?

No each Starter Pack should be a separate post FROM YOU, not attached to a post... It's cleaner that way, and easier for people to find... Also, when you post the link, add in the hashtag #StarterPack. because many people use that to find new ones...