Insert your USB stick in your Mac.
Restart your Mac and hold down the Option Key while it reboots.
When you arrive at the Boot Selection screen, choose “EFI Boot” to select your bootable USB Stick.
Select Install Ubuntu from the Grub boot screen.
Select Your Language and click Continue.
Click on “Install third-party software for graphics and Wi-Fi hardware, Flash, MP3 and other media.” Click Continue.
Choose “Erase disk and install Ubuntu.” Click Install Now.
Select Your Time zone and click Continue.
Choose Your Keyboard Layout and click
Enter your name, create a username and password and name your computer. Click Continue when finished.
Wait for the installation to complete.
Once the installation is complete, click the prompt saying Restart Now.
Connect an Ethernet cable to your system to gain Internet access if it doesn’t find the Wi-Fi drivers.
Run all Software Updates and rest