How does all this "paying the back taxes on a house" work? Am I able to get a house by just doing that?

This is a somewhat meaningless question that gets asked a lot.
If a town has a lien on a property that is worth about what the taxes in arrears are, then sure, you might 'get it for back taxes.' If the amount owed is less than market value, then the town will hold an auction or put it up for sale normally, and bidders bid low to factor in the taxes they will have to pay. Either way, you might be able to get a bargain, you might not. Often you have to have the balance in 30 days, so conventional mortgages are out.