How to check two other boxes (or uncheck them) if I check another checkbox.

[#1]

I have an Adobe form with fields that have a parent, child relationship.   

If I check (or uncheck) Check Box7  which is the parent,    which would indicate it is  Not Applicable,

how do I get the Child checkboxes   (Check Box 8,  Check Box 9,  Check Box 10)  to check or uncheck?

In addition,   a child should be able to be selected without selecting the parent or the other children Check Boxes.

So if the Parent field is applicable,    but  Check Box 9 is not applicable,  I would need to be able to check just Check Box9 without

it affecting any other check boxes.

I tried some of the suggestions I found online but keep getting syntax errors and was not able to use them....

Please help!