Windows has 2 versions of SketchBook:
a. Windows Store version does not have Flipbook. The icon is a orange square with pencil in it.
https://www.microsoft.com/en-us/p/autodesk-sketchbook/9nblggh4vzw5
b. Desktop version (Windows/Mac). This version has Flipbook.
www.sketchbook.com/thankyou
NOTE: (a) Windows Store version is designed for Surface tablets and is meant for use without a keyboard. It is a lighter version of SketchBook meant for that use.
David Lau