My understanding is this:
In the game, set your resolution to one of the following,
8002 E001 = 640x480
2003 5802 = 800x600
0004 0003 = 1024x768
What you seem to be doing is telling the game that the setting 800x600 will actually now be 1920x1080, for example. The example they give is if you begin the game with a resolution of 800x600,
Find (ctrl + F) ' 20 03 00 00 58 02 '
0320 in hex - 800 in dec
0258 in hex - 600 in dec
If your display resolution is going to be 1920x1080, you want to figure out the hex equivilent of those decimal values,
0780 in hex - 1920 in dec
0438 in hex - 1080 in dec
The site tells you to reverse the two hexs before writing them to the .exe; for example
07 80 needs to be 80 07
04 38 needs to be 38 40
The site seems to suggest also that there must be 0000 between the two values. So in summary, if you are beginning with a display resolution of 800x600, you will be searching this string in the .exe,
20 03 00 00 58 02 - Which is actually (0320)0000(0258), where the parenthetical shows where you reversed the two values of your resolution
You need to overwrite that string with your desired resolution, which if it is 1920x1080, has been figured out above,
80 07 00 00 38 04
The site then seems to suggest you will find a few other entries of the 800x600 hex string. You will need to search for and replace each of these strings with the new resolution you want. When you start the game, if you correctly edited the .exe, instead of drawing at 800x600, the game should now be rendered at 1920x1080.
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All I did above was try to explain what the wiki article was trying to explain. Hopefully this helps you out just a little bit; if not, perhaps someone else here could better or more clearly explain the process.