Personally, I like to make a general story outline first. What are the main events that take the story from start to finish and what does each character need to achieve? I keep this outline pretty brief. Once I’ve got that, at the top of each chapter I make something like this…
##Episode 1###########################
#Event 1
#Event 2
#Event 3- Important details here
#Event 4
#Etc.
##Episode 1###########################
Putting this at the top let’s be plan out the individual Episode within the script and make any important notes I may need when I reopen the portal. Hope this helps.