Plane Tickets

I called Delta to find out what I had to do to use my vouchers to get tickets. backstory: Last summer when I went to Florida, we took a ~3 hour delay in Orlando and in return Delta gave us (all 8!! of us), $400 towards future travel. They expire at the end of July so I'm trying to use them to go home for July 4th.
It turns out that I can use them on their website by entering the numbers. Originally I thought I had to go to the Delta ticket office (i.e. Sea-Tac airport) to redeem the vouchers. But alas I am saved! There's a decent airfare right now, so I'm going to try to book tickets when I get home tonight.