The title is pretty self explanatory. I heard that it allegedly could be done, but I'm a technological boomer and IT retarded and cannot work a non-user friendly program to save my life. So is there anyone who could help me out with this?

In particular, if I have an object downloaded and in my mod folder as a package file, and I open the file with S3PE, and I want to change that object's color, which is the tag (or whatever category that's relevant) that I need to edit?

My screenshot attached.

If the object isn't recolourable ingame with Create a Style, you'll want to click on each _IMG and check the preview until you see the one that is the main colour texture and export it to make your changes in an image editor like GIMP or Photoshop.
If it IS recolourable and you want to change the presets themselves, they're usually in an _XML resource- but those you'd likely want to tweak in TSRW in order to preview the changes.

fwiw, I think S3PE can be very user-friendly, it just has a bit of a learning curve to the interface if you're brand new to modding It's more the nature of gutting an object into its loose parts that makes it intimidating to know what it all does.

Is there a program that I should use to "check preview"? Where would I find the "_IMG" if not through S3PE?

Sorry for the confusion, all of the instructions were for S3PE.
The right-hand pane in S3PE is a preview window. When you click on each resource, it will show there- so when you click on resources with the _IMG tag, you will be able to see what they look like.
Many objects contain more than one texture, so it's helpful to look at each one in the preview to find the one you're looking for.

So you know... This was an object that I made recolorable a while ago. I saw similar post on another site, and directed OP to my dl.

Yes, thank you for that. Though with all due respect, the texture seems to be different from the original; I was able to get the color I want with yours, but I was hoping to also see if I can get the shiny texture of the original.

There is a bit to objects that is very different from garments. I have learned to manipulate much, regarding garments, but not so much with objects. To make that piece recolorable, I had to clone an object that was already recolorable, then change the script. Not sure what I cloned from, as most older work is on thumbdrive... if not lost.