You will need to have a little util program to flash your Bios with the new bios version in the bin file, you didn't said what kind of motherboard you got but just check the site of the manufactor and I am sure you can get the program there.
Than just make a bootable floppy with the flash util and bios file on it, reboot with the floppy and run the program.
*Some flash utils need to run like this: flashutil.exe biosfile.bin
*Others will ask the name of the file .. without giving you the option to select it, so write down the *filename because zx235BX.bin is hard to remember sometimes for example 🙂
Be also sure that you set your bios to be writeable, sometimes you'll need to change this with a jumber on your board but I also believe some bios's got this option in the bios settings itself.
*Before you flash it with the new bios, backup the old one (flash util prog got a option for that for sure) just in case your pc gives problems but you can still boot to set back the old bios.
G'Luck