I would put the substrate in the tank, add just enough water to cover the substrate, then plant the plants, except for the mosses. Then fill the tank carefully, using a sheet of Saran wrap or equivalent over the substrate to eliminate the incoming water moving the substrate around. Now, plant the moss - on flat rocks. Turn on the filter and turn on the lights for about 6 -8 hours a day. After 2 weeks or so, add 2-3 of the fish, preferably the tetras. Wait another week and add the rest of the tetras. Wait another week and add the rest of the fish, snails and shrimp. The plants should be growing before you start adding any fish at all, but that should take less than 2 weeks. Those plants will then help absorb the ammonia from the few fish, so they won't be harmed by the ammonia.