A Find and Sort are done in a layout containing the fields to be sorted or found.
You can freeze a window, go to a layout containing the required fields, do the sort or find, return to the original layout and refresh the window.
Each layout refers to one specific table via the table occurrence selected in Layout Setup|Show Records From.
Any find performed on that layout produces a found set of records specific to the current window, for the layout's Table Occurrence.
For more on table occurrences, see: Tutorial: What are Table Occurrences?