Actually, it looks like it might not yet be merged with the baseline, at least as of OH 2.4 M1. You might need to install a snapshot to get access to it through PaperUI, which I do not recommend at this time due to some major problems with the snapshots right now.
You will have to be patient, or run the snapshot I’m afraid. You might be able to manually install the add-on but I suspect it won’t work because of all the changes that are underway to merge ESH back into OH.