Notes to the milkman don't count.
Shopping lists for chocolate and stuff stuck on the fridge don't count.
Typing words into a search engine for research don't count.
Research is procrastination: "Oh, before I write this lengthy passage about crossing the plains on horseback I'd better check my facts on how much food and drink a laden horse requires per day. I'll just open up Google for a ... WOW! Would ya just look at these cat pictures?"
3 days later you've learnt new techniques for getting dried up pasta from a pan, a new recipe for baked leeks and you can hum the national anthem for Botswana, but none of those things count towards your NanoWriMo goal I'm afraid. And you still don't know how much horse a water needs to cross the food on plainsback do you?
If you don't know the answer to something, TK it. 'TK' is suggested as a place marker for something that needs to be checked out. At editing time. NaNo
WRIMo is about
WRIting.
NaNoEDMo is for
EDiting and that's in March. There's a whole month of parties to get through before then! So if you need to fact check then do it later, just write. Why TK? It's suggested because there are very few words in English that contain these two letters together so when it comes to editing time (in March, NOT November) searching for 'TK' should be a cinch. So long as your main character isn't called Altkin or something. Also if you're writing in a non-English language YMMV. Maybe use *TK if need be.
So "... He rode his horse for 2 days and nights across the plains. *TK [how much water does a horse need?] ..."