There is a WDC challenge each year that helps to prep for NaNo. It includes character sheets, practice stories, setting work and outlines. The challenge goes all month but have to sign up beforehand.

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October Novel Prep Challenge  (13+) A month-long novel-planning challenge with prizes galore. #1474311 by Brandiwyn🎶

I'm a pantser. I even didn't pick a novel one year until Midnight on day 1. Most times I try to pick the story at least a few days in advance. However, the prep can help whether you look at it all during the writing month or not. This year I'm doing a rewrite, but most years I just pick one novel out of the many and start writing on November 1.