So many courses- Where can I learn to launch a debut book?

With the direction traditional publishing seems to be taking, I'm considering indie publishing my children's picture book series instead of pursuing a contract. I need to grow my platform either way, and I have some plans for how to go about that.

But once my platform is stronger, with the book launch blueprint gone, WHERE CAN I LEARN TO LAUNCH A BOOK?!! And for anyone who's used crowdfunding, how do you have any fans left for your launch team, if they've all already purchased a copy of your book on Kickstarter or Indegogo? Where can I go to learn all of this?

Thanks!