Welcome to the community @canuck!
Unfortunately this is the limit on the Free Account plan so you would need to upgrade to the Lite Account plan ($24 per month) in order to unlock additional pages on your staging (webflow.io) sites.
This has been brought up within the community previously and I hope it’s something that’s addressed by the Webflow team going forward. Personally I think providing free users with a “tutorial” project that has a slighter higher page limit would be a good solution, but unfortunately I can’t speak for the larger plan for this specific situation.
In the meantime, you can always modify the project to fit more in line with a single page layout (putting each page within it’s own section on the homepage) which would allow you to complete the tutorial and work around the two static page limit. Not ideal, but hopefully it gives you the opportunity to fully explore the possibilities without needing to pay until you’re ready.
Hopefully that helps