Files for the Gigabyte GA-H81M-DS2 motherboard in a 1.57 MB zip. The name does not say whether it is firmware or documentation, so inspect the files after extracting. If it is a BIOS image, write it to the SPI flash with a programmer, and confirm the image size matches the chip. A schematic or boardview would help you check power rails, find shorted components and locate test points. Always compare the revision on the PCB, and back up the existing chip before flashing.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @schematicslaptop. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip