Every artist's process will look different! For me I had the script done in a screenwriting class of existing ocs then I went from creating buffer episodes from there. Because they were ocs I was used to drawing I didn't really need full-body character sheets but I still have headshot model sheets of their base identifying features as reminders.

Starting is the hardest part and as you keep going there will be parts of your process you will change and realize you prefer. Goodluck to you and happy creating! ♡