An now I want to know if I can garnish their income tax.I want to know what the next step is in order to get my money.

This is the catch 22 of getting a judgment. It is easy to win a judgment, much harder to collect on it. While it is possible to attach an income tax refund in certain cases, its very complicated. You need to ask the IRS what the process would be.

Its easier to garnish salary (if local laws allow) or attach bank accounts, if you know where he banks.

Once you have that information you apply to the courts for a writ of execution and have it served on his employer and/or bank.

It is harder to garnish IRS, the rules and process very complicated. As noted, finding and attaching local bank accounts is often the best way, after that garnishment of their paycheck ( if your location allows this)

As noted before, winning in court is easy, actually ever getting your money is another.