Is it possible for me to return to the old Gmail screen without the categories tabs?
Would my only option be to move to another email provider?
I cannot understand most of the computer "language", and am so lost.
Yes (at least for now).
Click the arrow next to your Inbox on the left side. You'll get a menu like this:
Choose one of the other options. It eschews the category tabs, but does group your email based on other factors, like whether you've "starred" a message or Google's algorithms have determined it's "important".
If you don't like those groupings either, you can change that in
Settings > Inbox.
Just change the options to remove the groupings you don't want. (Obviously you'll want to keep "Everything else".
Alternatively, you can simply get rid of all the tabs (except "Primary"), and you'll essentially just have the old-style Inbox.
Pull down the "Gear" menu and choose "Configure Inbox".
Simply uncheck everything except "Primary". (In fact, you're given the hint that you can "Deselect all categories to go back to your old inbox.)