What you need to research just so you know more about it, is called tank cycling process. This process can take 8 to 10 weeks, and there are several ways to do it.
1. Get a couple of hardy fish leapard danios or blood fin tetras, something inexpensive, there a very good chance that some will die. add 3 or 4 to the tank and feed them and maintain them as ususal, except don't replace any filter media or gravel vac the whole tnak at one time, I like to divivd the tanks footprint (bottom ot the tank) into four sections and only vacume one section each week and rotate it weekly. What your doing is creating a biocolony in the gravel that converts ammonina into nitrates and nitries. These are the things you want to test for.and when they get to dangerous levels (.20) do a water change. After 2 months you will or so, your tank will be cycled to start adding fish to the tank that you want to house slowly. There are no real ways speed up the process but what you can do is add a bio-colony to the tank. I fyou can get some dirty gravel or filter floss and use that it has a god amount of biocolony in them to seed the tank. Also live plants have an establish biocolony arounf there root bulb so adding them will help and there are also products you can buy that claim to make a biocolny in a few days, imo that is bunk becuase this is a thing that happens over time. what your doing is make the water safer for the fish instantly.
2. is call a fishless cycle process which you use pure ammonia instead of a live fish.
If you haven't yet invest in a liquid testing kit, it seems costly now but with the number of test you can do per area of intersest over time it saves money. Also, they are very accurate, unlike the test strips that are effected my the humity in the air.