Form Displaying error message below the text field

Hi
We managed to align the error message below the text field of the form using css (see the attached image) but we have another requirement to display multiple such messages for all the required field once submitted.
Right now if I click submit button with all the required fields empty only one error message gets displayed on whichever field the cursor was present.
How can we show error messages below all the required fields after a submit is pressed once.
Thanks
Parthiban G​