Make the fields themselves the button. You can select one button or multiple buttons and use Button Setup in the Format menu to turn them into a button. It may be easier to select each field one at a time and set them up as a button.
This is not always the best approach.
Put the button behind the fields and make it 5 or more pixels wider to the right or the left of the field on that end. Select the fields and use the behavior settings to change them to deny access in browse mode. Now clicking on the field will drop through to the button underneath.
Both options have pluses and minuses so I suggest duplicating your layout and testing both approaches to see if either work better for you.