You can Download the firmware here: https://github.com/seemecnc/Firmware

Extract the files from the zipped folder.

If you are new to extracting files, you will need to go to the folder where the firmware was downloaded to (most commonly your downloads folder)

Right Click on the folder named: Firmware Master, and from the options available choose EXTRACT ALL.

Choose Extract in the dialogue box that pops up.

You can now copy and past the extracted folder of firmware files to your preferred location ie. Desktop, My Documents etc.