The main site has stuff https://www.choiceofgames.com/make-your-own-games/choicescript-intro/
Once you’re done with that the wiki’s a good place to start http://choicescriptdev.wikia.com/wiki/ChoiceScript_Wiki
Choice of Box is meant to be a resource to help too. http://www.choiceofbox.com
I made a tutorial . A Basic Tutorial on Name, Relationship and Gender Variables that should run you through the basics (and you can see how it works if you copy/paste it into the IDE.