Requiem makes some significant changes to the game. Some of these changes are applied using external tooling to both Requiem and third party mods in your setup. You therefore need to generate a patch plugin for your personal load-order as part of the installation process. This patch plugin is created by the Reqtificator and is called Requiem for the Indifferent.esp .
In addition to Requiem itself (available at NexusMods), you will need the following dependencies as well:
Furthermore, the following SKSE plugins are highly recommended. These are important fixes for Skyrim bugs that significantly affect Requiem gameplay.
The content of the Requiem for the Indifferent.esp depends strongly on your load order. You need to recreate this patch by running the Reqtificator again whenever you add, remove, update or reorder any plugins.