Buying property for back taxes

[Kevin E Ruth]

I am looking at a local property in Waukesha County Wisconsin that I see has 4 years of back taxes owed (including the acre plot behind it both same owner). I know that no one is living in it as I have passed by the property hundreds of times in the last 4 years and no one is there. All winter the driveway is never plowed (dead give away in Wisconsin). Besides making sure there are no other liens against the property what is the best way to start the process of buying this property. Love the school district and location for a rehab and resell.

Thanks in advance for any insight,

Kevin