You have already rooted the phone so the next step will be installing a custom recovery. To do that you will need to download the sdk manager which has the necessaty adb shell. You also must have the correct drivers. In the stickied guide in this forum you will find detailed guides on how to do each step.
To summarize:
. Acquire correct drivers
. Root
. Install Sdk manager on windows and let it update
. Install custom recovery to phone via adb shell
. Install ROM from custom recovery
Follow the guides available here for each step. There well written. The only problems I had were figuring ouy what adb shell was, having to update sdk manager, and having to install arious frameworks in windows. Also do not type the pound symbols the guide shows when using adb shell in command prompt. That confused me as well.
Find your guides, get started and come back with a more specific question.
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