At this point doesn't matter if on a mac or pc. Or you can download it straight to your phone. Either way you need to rename it update.zip place it on the root of your sdcard, then boot into recovery (hold x+power button) when there go to install, then select allow update.zip (screen will just flash), then select sdcard update (deprecated) can't remember exact wording but its option 3. Then when its done reboot.
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