Browse a file and read its values

I have a button in my file which opens a dialog box and gets an excel file path.

Now how can I read values from that browsed file.
details

If the file name obtained by that button is e.g. "D:\temp.xls"

that button reads and place the file path in cell C3 as D:\temp.xls

How to read any value from D:\temp.xls?

Thanksssssssss