Get your new blade ready to mow.
All new blades come coated in a layer of lacquer to protect them and prevent rusting in transit and storage. Before first use it is best practice (but not 100% necessary) to scrape this lacquer off the cutting edge of the blade. This prevents it clogging up your stone when sharpening.
Using the end of a file, a rubberized sanding block or some emery cloth, scrape the lacquer off the cutting edge and up to 3-5mm back. As you will be working on the sharp edge it is best to wear work gloves to protect your fingers. There is no need to remove the lacquer from the rest of the blade