Take a raw shrimp (not cooked/frozen), put it in a mesh bag or new ladies nylon and drop it in the tank to start the cycle. Monitor the ammonia level to get to 5 or 6 ppm. If it doesn't reach that with one shrimp, you may need to add another. You need to keep this source of ammonia until you fully cycle (nitrite spike, then nitrate). Once nitrates spike and nitrites and ammonia are 0, you've completed the cycle. Remove the shrimp, do a PWC, and add fish.
You need to add the fish once the shrimp is removed to continue the source of ammonia (or keep the shrimp until you can add the fish).