Sequence Settings - Editing Mode and Video Previews?

Here you have a good reference Create and change sequences in Premiere Pro

how do I know if I am using the correct Editing Mode and Video Previews settings?

You have to know what you're doing, and how those various settings interact.

I went to a trade school to learn this stuff.  It's a good route, I recommend it.  But these days there are far more online options as well.

The best way to get sequence settings is normally to simply move a clip of your standard media to a timeline area ... drag/drop from Project panel to a blank timeline panel, drag/drop onto the New Item icon lower right of the project panel, right-click "new sequence from clip" option ... all work. Don't worry if it says something like "Arri X" or whatever, as what it does is look at the specs for the clip involved, then go down alphabetically through the list of sequence presets to find one that matches your media.

If you have specific needs, you can of course modify a preset or current sequence, save that as a new preset. I recommend giving it a name so it appears at the top of the list in alphanumerical sorting.

Neil