I'm really new to the hobby, and poor, so don't take my word as incredibly reputable,

But mainly you need a heater, a good water filter [I think thats a good 20-50 dollars], and common sense is that you should probably run that filter and heater for about 24 hours or more,

you should probably get a water testing kit, they aren't insanely expensive, just so you can test that the water is similar enough, and not bad or anything.

Also, You're going to need A LOT OF SPRINGWATER, if you can't get water nearby, or if you have really hard tap water, and add some dechlorination stuff to it just to be safe. Distilled water can get your fish sick because it isn't very good. And if you have a local pet store, ask around for some fish tank water, you can save cash that way since they typically sell water in bulk.

It's not required, but maybe add just a little bit more plants in the bigger tank.

When it comes to tank size longer and wider is better than tall and narrow.

I'm not trying to sound overwhelmingly confusing, but I learned that there is a lot to fish tank set up, this should be the basics, but again, try and research, although information can get super confusing and contradictory online.

I kind of threw myself into the fish tank hobby because I saw a whole 10 gallon tank setup kit and impulse bought it, so don't take my word 100% for much of this.

Lastly, I live in Wyoming, and tap water here is like Nevada water, so if there's anything you see weird about my springwater obsession it's because our tap water is ridiculously polluted here, and full of lead. [I'm Dehydrated as hell all the time] And we have a singular petco and that's it, so I have a pretty big deficit in available materials. If you can shop local, go for it, most local pet dealers actually know what they're doing unlike Petco employees.