The main unit is the SA-AK270. The entire mini-system is called the SC-AK270. The manual is available on the Panasonic support site: https://www.panasonic.com/au/support/manual-download/audio/hi-fi/sc-ak270.html
With the remote, press the Clock/Timer button until the Display is showing the time. Press Skip Back/Rewind or Skip Forward/Fast Forward within 8 seconds of pressing Clock/Timer to set the hour. Press Clock/Timer again and use the same Rewind/Fast Forward buttons to set the minutes. Note: the SC-AK270 uses a 24-hour clock.
You can also do this by starting with the Display button on the main unit. Then use the Skip Back/Rew and Skip Forward/Fast Forward buttons on either side of the Manual Eq button.
I hope this helps.