Well... there goes the weekend...
So many questions, so little time...
First, congratulations on the 'new' phone! You do know that you are already 'behind-the-times'; iPhone 8, iPhone X (that is the result of Apple's passion for using Latin instead of Arabic numerals, I guess). It appears that there will never be an iPhone 9!
Take the class at Verizon, it couldn't hurt. Just don't believe anything they say if they say I'm rong!
Your questions, as close as I can come to the order asked:
"...
apparently backing up things to the Cloud is important..." Yes, in the sense that you always want at least two backups of important info and in two different locations. You've already paid for this backup at Apple (it's probably one of their smaller puffy bumps on that humongous iOne). It doesn't cost anything nor does it count against the meager iCloud space. The worst thing about it is that you have to use iTunes. Start up iTunes, now connect your iPhone to your Mac.
On your first connection, you'll get to go through some steps that will confirm you are a trusted user of the iPhone and the Mac. You'll probably need your Apple ID password and, of course, the passcode for the phone. Once you get past these steps, iTunes should start up just by plugging your phone into the Mac.
[attachment=3539:iTunes_iPhone.jpg]
Click the tiny iPhone icon and you should see a "Summary" of the phone. The important section is the "Backups" area. It is probably already set to Automatically Back Up to iCloud. That's fine. BTW, you won't waste space in the cloud by backing up your apps. Since they are already "in the cloud" and Apple already knows what apps you have, the backup will just include a list of them, not an actual copy of them. Any data an app creates will be backed up, however, and that will take up space on the cloud.
You will also see another option to make a backup to "This computer". I do this whenever I have iTunes open, which is extremely rarely.
Just remember to change this setting back to iCloud. Actually, iTunes is pretty good at reminding you that you've made a change if you try to Quit of use some other function of the app.
[attachment=3540:iTunes_Backups.jpg]
Let's stop here and maybe some one else will come along and corekt my comments and/or answer some more of your questions. I knead a break...