What you need:
1: fixed gear (or flip flop) rear wheel, the front wheel you have now will work fine
5: short stack chain ring bolts.
Step 1. Remove the derailers, shifters, cables and rear wheel.
Step 2. Remove crankset, use new chainring bolts to secure single chainring to middle position of crank.
Step 3. Shorten chain, and replace.
Tada, you have yourself a new fixed gear, or single speed. Nine times out of ten, that's all it takes.