Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
The above article has a few things to help you learning Scoutbook for all Programs - including Cubs.
At top it has a large (over hour long) video going through the most important functions. This was made and intended to be a rather full tutorial for even group settings.
Then below that the video is chopped up into topics.