Massive sports card collection (Birchwood wi.)

I was left a huge ( MASSIVE ) BASEBALL/ FOOTBALL And misc.
Card collection and truly have no idea how to organize them to sell them.
A family member while looking through them mixed them all up.
Prior to being left the collection I was told there were rare and very sought after cards there are graded card and many valuable cards here.
If collectable cards are your thing here's your chance to add to your collection.
There are thousands of cards here ! Two big boxes of cards.
Come look and offer.
I'm taking offers as I've only know what we've been told as to their value Will conceder trading them all for a vehicle or side by side.
I only skimmed the surface to value them and found $2700.
Worth in 27 cards of the thousands.
Really not my thing.
Come look.