Welcome to the forum and hobby. One bit of advise that I would like to share is a very effective shortcut to cycling a tank. My first experience in the hobby was not very successful and didn’t last long. Unlike you, I jumped in without asking any questions. I knew nothing about the nitrogen cycle and now I know why I had so much trouble then. A few years ago I got interested in the hobby again and this time I did a lot of reading before I started. I read all about the nitrogen cycle and did not want to go through the difficulties of cycling my tank. I ordered an active sponge filter ( one already containing the benificial bacteria need to convert the fish wastes) from an online vendor. I had my tank ready and I timed my order so it arrived about the same time I added my fish and my tank was instantly cycled. If you know someone else in the hobby you could also arrange to get a used filter from them. It is really that easy. After that, test your water and keep up on your water changes. Good luck.