No Time Machine Icon shows in top menu, so can't show Preferences that allow selection of backup disks; opening the app brings up only the RESTORE screen

No Time Machine icon appears in the top menu bar of my MacBook Pro. (The icons for Accessibility, Bluetooth, Network, Sound, Battery, etc, however, do.) Opening the Time Machine app itself brings up only the RESTORE screen, with its cascade of past backups.

The machine's specs are:

MacBook Pro (Retina, 15-inch, Late 2013)

Processor: 2.3 GHz Intel Core i7

Memory: 16 GB 1600 MHz DDR3

OS: 10.13.6

S/N: C02MV08EFRG2

Without having the Time Machine's icon's drop-down window that shows Time Machine Preferences, I can find no way to select any backup disks.

I installed a fresh OS 13.6, emptied the trash, disconnected all peripherals, rebooted. Hasn't help.

I have two MacBook Pros, which may be relevant because the specs of the old one are those recorded in my Forum Account. I recently bought a new one (above described) because the old one was starting to fail - some of its keys had stopped working, though I can still use it with a wireless keyboard.

Old MacBook Pro Specs

MacBook Pro (13-inch, Late 2011)

Processor 2.8 GHz Intel Core i7

Memory: 8 GB 1333 MHz DDR3

OS: 10.13.6

S/N: C02H70KSDV17

Other than those failed keys, the Old Mac works fine (including its Time Machine). [I tried to copy Old Mac's Time Machine app onto New Mac, but of course in vain; Apple doesn't like that.].

So what, please, do I need to do now to back up my new Mac using Time Machine?