Alrighty kind of brief but Ill try to get you as much information as I can. First Step: Pick out some fish that you like but don't buy them, Do as much research on them as you can such as can they have tank mates, Minimum tank size, food, environment that they live in ect. Step 2: Set up your tank. Pick out substrate ( the bottom layer of your tank, rocks, sand ect) Some fish prefer different substrate but since you researched the fish you will know the best. (some fish don't care, but others need certain size to help keep them healthy....And some fish have better colors in darker substrate. Step3: Pick hardscape ( bigger rocks, logs, any decorations) Once again some fish prefer different things, Shells to hide in, PLants to hide in and just some things to keep the tank interesting for them.
Step 4: Cycle your tank....It get be done a few ways but you should research that because its very important.
Step 5; Add fish
Step 6: Amount of water changes differ depending how many fish you have, if you have plants a good filter ect.
Hope I helped abit, any more questions just ask!
Welcome AA you'll find it helpful and learn alot