Facing problems on setting default values for a field

I am Debasis. i am facing one problem while designing excel form. I want to
share with you that.

i have a field in excel form. whose type is "text". According to my
requirment when i pass any value in the 'label' column to this field, i
want that this value should come as a default value for annather field
whose type is also "text".

In the second field's 'default' column when i am writing ${Q_A_2} (
"Q_A_2" is the value of 'name' column of first field) it comes as like it
is.

So how can i populate that entered value of first field to the default set
value of second field.

Please guide me on this issue as soon as possible.

Thank you.