Start first with something small before attempting to make a long game. A short story to practice Choicescript and once you get the gist of codes then make your desired game.
Here is a list of helpful links; hope you this helps you create your game.
Master List: Links for Beginners
COG Game Design Guidelines
Tips for world building
Tips for you writers!
Tips for writing realistic (but not “too realistic”) dialogue
More topics are out there, you can use the search option on CoG to locate the topics you’d like.