Dont Rush
If u try to jump all the steps ull end up dissapointed and frustrated. There are a couple of things u need to do b4 stocking ur tank. Right now ur last fishes are in great danger.
Firts u gotta plan how u gonna cycle ur tank- right now ur levels might be at zero but they are all going to spike and it would be harder to take dm back to zero. It could take up to 3 months to fully cycle ur tank.
Firts u need some live rock and live sand (bout an inch)- they will help in the biological filtering. Then u take a pair of damsels to start ur cycle. Their poo, pee and food leftover will turn into ammonia. Thats just the beginning. Then they'll turn into a less toxic gas, nitrite and eventually into an even less toxic, nitrate. When ammonia and nitrite finally reaches zero and nitrate high thats when u know ur cycle has come to an end. To get rid of your nitrates ull have to make some partial water changes (pwc). For small tanks ull have to make more water changed since their is not enough space for the nitrate gases to detoxify or go away or wutever. This takes bout 3 months; then ull be able to stock ur tank.
A couple of products or tricks might help to get this cycle done faster. You might use BacterVital to accelerate bennefical bacteria ( this bacteria is the responsible to turn ammo into nitrite then nitrate). Then u might want to use sumthing like AmQuel to help detoxify em'. Most fishes will survive in a .20 ppm nitrate level. No ammonia or nitrite should be in ur tank, its too dangerous. A tank that small should be overstocked since these levels may rise in a blink of an eye. U might take some live sand from an already cycled tank and add it to urs- which I really wouldnt recommend doing anyways.
So, no need to rush. I tried doing everything faster and ended up killing them poor fishes and wasting more money than doing everything the right way. But I learned from my mistakes. Just calm down and enjoy the process.