Using the date/time picker, I know how I can make the user select the date alone by clicking on a button but I would like that by clicking on another button below he selects the time for that date. How can I do that?

By configuring the date picker action to select only date, it sets the time (in the variable where I store what the user selected as 'datetime' data type) to 12:00 AM by default.

I would like to add another button for the user to select the time for that date and update the variable . If I configure the action on that second button to select the time only and update the variable, it stores in the variable only the newly selected time without a date and therefore the variable becomes null.

How can I add the selected date to the selected time and store together in the same variable while letting the user select each of the date and time from by clicking on separate buttons?

Thanks