Reserve the highest demand week in your season.
Go to Redweek.com
Search for your resort. See the price range that others are asking for a week at your resort.
Place an ad on any of the following sites : Redweek, TUG marketplace, go-koala.com , airbnb, NextDoor.com, Facebook marketplace and Craigslist
All are free to list the ad, except Redweek. Redweek requires the annual membership, plus the fee to place the ad for 6 months. TUG has free listings for TUG members.
go-koala, Airbnb and ebay charge a fee on the proceeds.
I know nothing about Facebook marketplace (other than that it exists)