Power on the ATC.

Navigate to the main System Screen (PP/AWM/HP).

Launch HP Street Navigation.

Tap on Settings

To Set Time:

Tap on Time.

Tap on the two clock icon towards the bottom of the screen.

Uncheck both boxes on the screen.

Tap "Set Time Zone".

Select your currect time zone.

Tap "Select Time Format"

Select your desired Date and Time formats, then tap the Return arrow.

Tap the Return arrow once more.

Use the "Hours" and "Minutes" + and - to set the Time.

Tap on the Green Checkmark to save.

To Set Date:

Tap on Date.

Use the + and -  on the right side to select appropriate Year and Month.

Tap on the correct day.

Tap on the Green Checkmark to save.