How to cause a subform to update in Access after filling in a combobox on the main form

Question

I have a Query that I am using to fill in data on a subform. The query references in its WHERE statement two hidden textboxes on the main form:

SELECT *
FROM qun_TrainingSU
WHERE ([qun_TrainingSU].[Training]=[Forms]![TrainingsSU]![htxt_Training]) AND (EmployeeInformation.Employee = Forms!TrainingsSU!htxt_Employee);

The qun_TrainingSU query is a complicated union query of the format :

SELECT CompletedTrainingsNew.Employee, CompletedTrainingsNew.AbuseNeglect AS Compdate, AbuseNeglect+(SELECT Expdays 
FROM Trainings 
WHERE Trainings.[Training Name] = "Abuse & Neglect"
) AS Expired, EmployeeInformation.[Last Name], EmployeeInformation.Employee, "Abuse & Neglect" AS Training
FROM EmployeeInformation INNER JOIN CompletedTrainingsNew ON EmployeeInformation.ID = CompletedTrainingsNew.Employee
WHERE ((([AbuseNeglect]+(SELECT Expdays 
FROM Trainings 
WHERE Trainings.[Training Name] = "Abuse & Neglect" ))))

With 22 other different trainings being unioned to this exact one. They are programatically identical, with only text changes as needed to change the various names of the different required trainings.

Both queries work alone. They are flawless (if amatureish) in functionality.

What I want to do, is create a subform on the main form, that calls the first query I listed, and allows for editing the records as need be.

I have tried going into the property sheet for the subform and doing links: I have two combo boxes that fill the two hidden text boxes (htxt_Employee, htxt_Training) I named the as Master (seen in the image below) and I referenced them to fields in the query as Child Fields.

Now, I think my problem is that I need to get the subform to update after both boxes are selected, so that the data in question shows up. And if that is the case, I need to know how to do that. I've looked, and I have found some stuff on manually updating the boxes, that may work for me but I am not the end user, and I need this to be pretty much automatic for them.

Can someone point me in the right direction here?