Install as an individual facilitator

TL;DR No admin center? Use PowerPoint on the web (Upload My Add-in) to try it, or the Mac copy-paste install below. Windows desktop without admin access should wait for the store listing or ask an admin.

PowerPoint on the web (fastest way to try it)

Open PowerPoint at office.com and open any deck.
Insert → Add-ins → Upload My Add-in.
Upload manifest.xml, and again for manifest-content.xml.

Web uploads may not persist between sessions — fine for evaluation; for daily use prefer the admin-center install.

Mac desktop

Download both manifests.
Quit PowerPoint fully (⌘Q).
In Terminal:

WEF=~/Library/Containers/com.microsoft.Powerpoint/Data/Documents/wef
mkdir -p "$WEF"
cp ~/Downloads/manifest.xml "$WEF/facilitator-tools.manifest.xml"
cp ~/Downloads/manifest-content.xml "$WEF/facilitator-tools-live.manifest-content.xml"

Reopen PowerPoint. The Facilitator Tools button appears on the Home tab; the Live Results frame appears under Home → Add-ins.

Windows desktop

Windows has no simple manual install — use the admin-center route (most solo subscriptions include admin access) or PowerPoint on the web until the Microsoft AppSource listing is available.