Investigate Quantum's SaveFileDialog function.  Evaluate (SaveFileDialog).  Note that though (SaveFileDialog) generally returns a String file name, it does not actually "open" anything.  SaveFileDialog's "work product" is just to produce the String.  Similarly, (SaveFileDialog TRUE) will generally return a String file name, but it does not actually "save" anything.  To do actual opening and saving, an application must include additional code following a SaveFileDialog function call.

Example:

Reference Manual: File System