How can I activate the self hosting without uploading to the shapespark servers?
Self-hosting is available in the Plus plan and with the perpetual license. When you have one of these license types, you will see a Bundle button in the scene list. Clicking the button will generate a self-contained set of scene files for your WWW server.
More information: https://help.shapespark.com/hc/en-us/articles/360009008278-Host-scenes-on-your-own-server-Plus-plan-or-perpetual-license-