its too simple.first, you have to find any patches for w810i.patches must be compatible your main firmware.
open gslide.
select your main firmware.
select header for firmware.usually 344 blocks header required.if your patches too bigger for this header, try 367 blocks header.
add patches.
set output file name and folder.
press process.
your new patched firmware will be ready.
when process done you must be flash your new patched firmware using xs.