What form do I use or how do I report the sale of undeveloped property? This was not a business property.

You enter that as an investment sale in the Wages and Income section of TurboTax, then Investments Sales, then Stocks, cryptocurrency, Mutual Funds, Bonds, etc... Skip the section where it asks if you want to upload your tax documents. Choose Other as the type of investment you want to enter. You'll come to a screen where you can enter in your sales proceeds and cost basis: