Use SE51, enter program name as SAPLXCO1 and screen name as 0100 and create it as subscreen (attributes section).
Click on Layout button create field descriptions and fields. The field names will appear in element list tab.
You can control these field (if you want allow input or make they grey out) in the include ZXCO1O01
Sample code below:
module screen_fields output.
*
loop at screen.
if screen-name = 'AUFK-ZZ_CUSTOM_FIELD1' or
screen-name = 'AUFK-ZZ_CUSTOM_FIELD2' or
screen-name = 'AUFK-ZZ_CUSTOM_FIELD3'.
if sy-tcode = 'CO03'.
screen-input = '0'.
else.
screen-input = '1'.
endif.
modify screen.
endif.
endloop.
*
endmodule.
