On the value tab of the one you want to be mandatory set the type to User Entered Required. In order to type something into the field they have to enter and exit the field. Put a script in the exit event to check if the field is empty and if it isn't then set the "other" fields access property for...
You're adding an instance of a subform but you're always referring to the first instance while setting the rawvalue. In your case PageSix.Table7.Row1.Risk would be something like PageSix.Table7.Row1[1].Risk to refer to the instance you of course can use instance manager to get the count of the rows...
Either on the TTime script set the Total by using the same method you're already using to get the TTime. Total + TTime. If you put the calc on the Total field then you'll have to iterate through the table to get the TTimes.
Your document has been protected you need to have credentials to open it, whoever provided the document or your IT team should be able to provide the correct information
You can’t post the form online, have a user download it, and then have them submit data to you more than 500 times. You can’t distribute the extended form to more than 500 people.