Use the compatibility tables (this link will go straight to Apple's official website) to find the Windows support software (drivers) you need for the version of Windows and the Mac that you're using.
Click the link in the table to download the related software.
After the file downloads, double-click it from the Finder to decompress (unzip) it.
Open the resulting folder. Locate the following files in this folder and drag them to your USB flash drive. When prompted, if you want to replace the existing items on the flash drive, click Yes.