Do you have fish yet? If not I recommend you do a fishless cyle. It is by far the least stressful (for you and your fish) way to go. Cycling with fish means constant water changes for you and stress (and likely deaths) of the fish due to ammonia and nitrite exposure.
You should read up on cycling if you haven't already.
For test kits, the most important are ammonia, nitrite, nitrate and pH. Get liquid tests rather than strips as strips are inaccurate and often don't test for ammonia.
In a cycled aquarium ammonia and nitrite should be zero. Any higher causes stress for the fish as both are toxic to them.