How to declare long term capital gains from International property (house) sale? If we invest proceeds in USA on property (house) can we offset the gains?

Please note that if this foreign property was considered your primary residence, then you do not need to enter the sale of your foreign primary residence if:

• You meet the home gain exclusion. You can take the gain exclusion as long as you considered the home your "primary residence" for 2 of the last 5 years. If you have a capital gain from the sale of your main home, you may qualify to exclude up to $250,000 of that gain from your income. You may qualify to exclude up to $500,000 of that gain if you file a joint return with your spouse.

If you are not able to exclude the gain and need to report the long-term capital gain, this would be entered in the Investment sale section.

Click on Federal > Wages & Income

1. In the Investment Income section click on the Start/Revisit box next to Stocks, Mutual Funds, Bonds, Other.  If you have already entered some investment sales, you will see a screen Here's the investment sales info we have so far.  Click on the Add More Sales link. 
2. If you haven't yet entered some investment sales, you will see a screen Did you sell any investments in 2022?  Click the Yes box.
3. On the screen,  OK, what type of investments did you sell? mark the Other box and click Continue.
4. When you get to the screen, Now we’ll walk you through entering your sale details, enter the details of the sale.  You will be able to select the type of investment in the first box [second home, land, etc.]  
5. Enter the requested information and click Continue when done

You cannot offset the gains from the sale of a foreign house if you purchase a house in the USA. 

If you have to pay taxes on the sold property in the country where it's located, you may be able to claim those taxes as a foreign tax credit on your U.S. return.