Download the target file to your Macintosh.
Once downloaded, the Installer Disk Image will be mounted on your Desktop. You will find the installer package icon "xxxxxxxx.pkg" on the desktop.
If you don't find the installer package icon, please extract the "xxxxxxxx.dmg" file manually with "Disk Utility". "Disk Utility" can be found in /Applications/Utilities. "dmg" is called "disk image file". This needs "Disk Utility". By using "Disk Utility", the Installer Disk Image can be mounted.