Nice sized tank. Most beginners start with a small one and that's not good. The larger the tank the more forgiving when it comes to tank management. The first thing to do after the tank has been set up with bottom material, heater, filter and water treated with an additive to remove chlorine and chloramine, is to add floating plants. Floaters like Water sprite, Hornwort, Anacharis or some of the others will help steady the water chemistry and make it ready for fish, provided you decide to cycle the tank with some hardy species like Guppies, Platies or Sword tails. These are all livebearing fish. If you prefer egg layers, then Rasboras, White clouds or Danios work well.
You add 3 to 4 fish or every 10 gallons of water to be cycled. Feed a little every day or two. The dissolving fish waste (ammonia) combines with oxygen from the outside air and begins to grow the bacteria colony. The microscopic bugs that use ammonia and nitrite for food. Test the water daily for traces of ammonia and nitrite. If you have a positive test, remove a quarter (25 percent) of the tank water and replace it with tap water treated with the additive to remove chlorine and chloramine. Don’t remove more water, it starves the bacteria and slows the process. When several daily tests show no traces of ammonia or nitrite, the tank is cycled. Once cycled, in a month or so, you change out half or more of the tank water weekly to maintain a healthy water chemistry.
There you have it. Have fun.
"Fear not, my young apprentice. Just change the tank water."