There are two useful things:
1. The in-app manual. Type in a valid keyword and press the [?] button. That'll tell you what that keyword does.
2. The reference on SmileBoom's SmileBASIC website: smilebasic.com/en/reference
Also, I suggest you experiment with the commands and functions. That is how I learnt SmileBASIC over two years ago.
The video stops because SmileBASIC has a limit of 8MiB shared variable memory.
The video was around 8MiB.
I had to compress it so it was less than 4MiB.