please spend some time reading the "setup and filtration" section of the forum to properly understand the requirements of your fish, you cannot just "learn from mistakes" as they come, you gotta be proactive and do research and prevent mistakes.
We were all once beginners and ignorant in fishkeeping and there is no shame in it. there needs to be a steep learning curve in order for you to create an optimal environment for your pets. You will be much happier with them once you know that you know what you are doing.
good luck
