Order of Publishing: Step Sequence (and Printing)

( I put this into another conversation, but then realized i should just start a new thread.)

I'm a little foggy on the order of possible steps to take, once my children's book is ready to publish? What am i missing, or is there a better order? These questions assume editing, illustrations, formatting and deciding on a price are all done!

Get ISBN (and UPC?) to include so I'm the owner, always
Publish on KDP
Set up business accounts for Instagram & Facebook for the book/s
Set up a Shopify store / website (it's both, right?) for selling books (direct to consumer, to bookstores, to schools, at book fairs, etc.)
Order books to have personal inventory (from where, exactly? Mixam? or where?) so that you can sell DTC (on Shopify and in person (see above)
Start promoting like crazy
Add in all the other stuff: Stickers, coloring pages, downloadables, etc.
Where does Ingram Spark fit into all this? Or does it? Wowza! Thanks for being a place I can ask all this! :)