Use the factory method to display the ALV in Popup.

DATA: gr_table           TYPE REF TO cl_salv_table,
*<< Your Custom table, Populate data in it gr_master TYPE STANDARD TABLE OF ymaster, lr_functions TYPE REF TO cl_salv_functions_list, lr_columns TYPE REF TO cl_salv_columns. TRY. cl_salv_table=>factory(
        IMPORTING
          r_salv_table = gr_table
        CHANGING
          t_table       = gr_master ).
    CATCH cx_salv_msg.
  ENDTRY.

  lr_functions = gr_table->get_functions( ).
  lr_functions->set_all( 'X' ).

  lr_columns = gr_table->get_columns( ).
  lr_columns->set_optimize( 'X' ).

 gr_table->set_screen_popup(
  start_column = 1
  end_column   = 100
  start_line   = 1
  end_line     = 20 ).

  gr_table->display( ).

Check out all the ABAP ALV Tutorials.