Maybe this will help.
LTG : )
MAC FULL INSTALL INSTRUCTIONS
-- Download the full install .iso file
-- Start Disk Utility in Applications/Utilities,
or type "disk utility" into the spotlight search bar (magnifying glass in upper right of screen)
-- If needed, click on "View - Show All Devices" to see all of the devices and their volumes on the left side.
-- Insert USB stick, and once it appears in the sidebar of Disk Utility, highlight the device name, not the volume name.
-- Click "Erase" button and set the format to "MS-DOS(FAT)" using scheme "Master Boot Record" with name "JJPUSB"
-- Click "Erase" to start the formatting process.
-- Double-click the previously downloaded .iso image file from Step 1
-- This should mount the iso file and open a Finder window showing its contents
-- Open another Finder window and on the left side click on the name of the USB stick you formatted in Step 3,
which should show a blank window because there are no files on it yet.
-- Select all of the files in the iso file Finder window from Step 4, and drag them into the empty Finder window
from Step 5. This will take some time (20-30 minutes) to complete.
-- Once the copy is complete, click on the little "eject" triangles next to the iso image name and the USB stick name
on the left of a Finder window.
-- Once the names disappear from the Finder window, remove the USB stick from the computer.
-- Use the USB stick to install the new version in your game, etc.