When installing ITSI to support a Distributed Search Architecture, focus should be on the location of the files within your Splunk environment. Copying SA-IndexCreation to the index cluster master node's etc/apps directory ensures that index configurations are managed properly across all indexers. Extracting the installer package into the etc/apps directory of the cluster deployer node ensures that the ITSI components are properly distributed to the indexers. Additionally, extracting the ITSI app package into the etc/apps directory of the search head makes the ITSI app available for user interaction. Hence, these steps (B, C, and D) ensure that ITSI is properly installed and functioning in a distributed environment.