1. To apply the patch, make sure to have an F-ZERO X (U) [!] ROM or else you may have a screwed-up ROM or the ROM will fail to load. For legal reasons I will not provide a link to one but if you Google for one, you will find one eventually.
2. Download Lunar IPS. Google that too and you will find it eventually as well.
3. Upon loading Lunar IPS, it should register the *.ips file type.
4. Double-click the patch in the archive. Then select the ROM to patch making sure to change the drop-down that says Most Common ROM Files to All Files (*.*) or else the F-Zero X ROM will not show! I recommend making a copy of the ORIGINAL ROM and rename it to "F-Zero UchiX ~Side B~". If you see ".n64" or something at the end of the file name, leave it there. Alternatively you can click Apply IPS Patch in the Lunar IPS window to first search for the patch and then search for the ROM to patch. Just make sure to extract the patch to the desktop first!
5. Enjoy the hack!
6. (original instructions taken from Relm’s readme file since the instructions are identical)