Parallel is .5ohm and series is 2ohm. I "assume" your amp will want it at 2ohms. Connect 1 POS & 1 NEG from each coil together and run the other POS/NEG to the amp...
If you wire them in parallel, you'll get a .5 ohm load. If you wire them in series, you'll get a 2 ohm load. Those are your only choices, if you have only one sub.