i am afraid you will have to download a manual from somewhere to learn it
as the name suggests its a basic langauge pretty much
i found many old journals which actually taught you how to create 3d shapes with basic code
with step by step code commands written
Finding out how to get the code exported was fun
But the code itself was unreadable
still amazed by the fact that there is PRG studio which actually helps to edit C64 game code
Coding BASIC now is much more sane than in the old days
now you have decently modernized BASIC tools
your code took like eight years to compile
warnings, if those even existed, lacked any detail
and you had no intellisense
also, no internet to look shit up on
if you were lucky, you could head to Usenet or a BBS
but that wasn't accessible for everyone
Yes and also the fact that the game data (Sprites, text, etc.) is part of the code instead of a separate file