Download the zip file and extract to your SD card. Make sure the directory structure from the zip file is preserved, so you end up with a ‘sd2snes’ directory in the root of your SD card.
Insert the card into your sd2snes and turn on the SNES. sd2snes will update its firmware from the card and boot.
After updating you may delete the ‘firmware.img’ file. You may not delete any other files from the sd2snes directory.
The ‘sd2snes’ directory is considered a system folder and ignored by the file browser. Do not put any ROMs there as they will not show up 🙂
The headerless BS-X BIOS is required for running BS games. Rename it as ‘bsxbios.bin’ and put it in the sd2snes directory.
For DSPx / ST0010 support you need the DSP ROM dumps:
They should be quite easy to find on the nets.