Inadvertently won auctions, closed on properties, now what?

[Anas B.]

I was wandering through the listings of the real estate auction website, auction.com, last month and placed bids on two properties I didn't think I would win.  Well, when the auction ended on the two listings, I ended up being the high bidder.  I closed on both properties this week.  Both properties happen to vacant lots that used to have single family homes on them and have since been demolished (one for being burnt down and the other for code violations).

The thing is, I'm not really sure what to do with the lots.  Should I try to resell at a higher price? Should I build and then sell? Should I try to apply for a multi-unit permit? What would you do?

The addresses of the two properties are:

426 Doty St, Fond Du Lac, WI 54935

221 E Lexington Ct, Fort Wayne, IN 46806