Well, I suggest you set up the tank first and not get the fish right away. I made that mistake. Walked through the mall and on impulse bought a tank and a few fish right away. They died a few days later. So, I learned from my mistakes. You must realize, that goldfish are heavy waste producers and with the right conditions will grow very large, so getting a 10 gallon for a few goldfish is really cruel. The larger the tank and the less fish you have, will be the best conditions for your fish to thrive.
Also, start with one fish, to get the tank to cycle. Then slowly introduce tank mates. Hope this helps.
I use to keep a couple of freshwater tanks, but gave up the hobby a few years back. But it was nice, and my children and myself enjoyed it. It’s big responsibility.
I have had fish all my life and my advice is not to get them if you are not going to take care of them. I know people who were excited to get a goldfish but after a few days the completely forgot about it if you are going to get it take care of it.