Does taxable gains apply to buildings on leased land? Not considered as real estate but personal Property? sold a cabin and bought a different cabin on lake leased lots

Yes, assuming the cabin is used as a second home/vacation home it is a personal capital asset and gains on the sale of the asset are capital gains.  (Note- Sale of personal property, such as vehicle, for more than the purchase price is also a capital gain)

To enter an investment sale other than from a brokerage account (1099-B), follow the steps below.

• Click on Federal Taxes (Personal using Home and Business)
• Click on Wages and Income (Personal Income using Home and Business)
• Click on I'll choose what I work on (if shown)
• Under Investment Income
• On Stocks, Mutual Funds, Bonds, Other, click the start or update button

On the next screen, click Yes

On the next screen, click No

On the next screen, choose the option that pertains to the type of investment sale you are reporting and continue with the section until it completes.

Or enter investment sales in the Search box located in the upper right of the online program screen.  Click on Jump to investment sales