Fishless cycle?
If so, google fishless cycle and read about it there.
To summarize it:
-Setup tank with gravel, heater filter and lights. Plants if you're going to use them.
-Up the temperature to 28c if you want it to cycle faster. (Optional)
-Add five drops of ammonia then measure the ammonia level using your test kit.
-If it has risen to 5ppm, then leave it. If not, add more.
-Once at 5ppm leave the tank running. Test everyday, maybe twice a day.
-When it drops to 1ppm then add more until it's 5ppm
-Continue this until you have to add quite a bit of ammonia to get 5ppm
-Then leave the tank, measure the Nitrites, they should spike
-Then the Nitrates will spike
-Done!
HTH