Visual C++ saving in a file

Hi,
I want to save some data in a file, but I want the user to be able to choose the name and the placement of this file. In the menu of my application I already have a menu with save as... if I click while executing it opens a windows window that permits me to browse. How can I interact with this window to get the file name and the path for the file?

And second question: how do I call a Document function from the main frame (menu)?
Thank you for your answers.