Everybody does things their own way in this hobby. There are very few universals.
For example, I always place my heaters horizontally near the the bottoms of tanks. There are several reasons I make this choice:
1. Heated water rises. So the heating part of the heater being lengthwise will emit heat over a greater range. This will move more water up from the bottom part of the tank to the surface. This means heating will be more evenly spread, plus it will help cirulate more water from the bottom towards the surface.
2. The positioning means I can easily lower the tank water by 50 -60% during weekly water changes and never need to disconnect the heaters(s). Over time most of us will forget either to unplug them before we lower the water level or forget to plug them back in afterwards,
3. It is easier to hide heaters behind rocks/wood/plants so they are out of sight in a display type tank.
But as I said at the start, this is my way of doing things and not the only way by any means. I use a canister filter on some of my bigger tanks and this lets me use an inline heater which resides outside the tank and the issues that I deal with for typical in tank heaters do not exist for the inline heaters.
You have just embarked on a journey that can last a lifetime. Keeping fish can be a ton of fun but also some work. It can also be a great learning experience. There are also Aquarium clubs all over the country. But when I clicked on your location I discovered the is and Ely in 3 different states so I cannot point you towards a potential club. These are great resources. They welcome new fish keepers and members enjoy helping them, so if you have such a club near you, I would urge you to attend a meeting.
Most clubs invite new folks to attend a meeting before they join. Most clubs charge nominal dues (mine charges $25/year) but they also hold auctions at their monthly meetings. You will get a chance to buy a lot of neat fish raised by the members and sold for wat less than you might find them in stores or online. More importantly you will learn a ton frompeople who have gone through what you are now. All of started out as newbies
edit to add this p.s. Go here and read for help understanding the basic water chemistry:
https://fins.actwin.com/aquariafaq.html
Most of the info there id pretty accurate, but some is a bit off, The stuff that may be off a bit is the more advanced stuff and you need not worry about it for what you are doing. But the explanations of the basics you should know are very good. They will give a good starting point from which you can ask questions.
edited for spelling and typos