I find your test results odd for ammonia, nitrite and nitrate if the only thing you added was the Tetra Safestart. Did you add anything else to the tank besides the gravel, fake plants and rocks?
I would also try testing your tap water doing all 4 tests and post your results. I'm curious if you get an ammonia reading and if so, it would be because your tap water is treated with chloramine instead of just chlorine.
Do be sure follow the testing procedure exactly which includes shaking the nitrate reagent bottles thoroughly before dispensing the drops into the test tube. This step is often missed by newbies when first using the API test kit.
Also be sure to thoroughly rinse out the test tubes and caps after you are done testing and allow them to air dry. Most people use tap water to rinse the test tubes but it would be better to use RO (reverse osmosis) or DI (deionized) water according to
duanes
especially if your tap water tests show an ammonia, nitrite or nitrate level above zero.