You can make a field required, but it will not keep them from proceeding to the next field without completing the previous. However a warning message will be generated if they try to submit without that field being completed.
To make a field required, you need to open the Object menu. Go to the Value tab and under Type, change to "User Entered - Required" You will have the opportunity to enter a message that the user would see if the left the field blank. Required fields will show up with a red border around the field if the user has highlight fields selected.
Hope that helps.
