How exactly does the Lamp of Alhazred work?
This was explained in the original Limited edition of the rules, but has been omitted from more recent versions (since it’s the only Artifact that works this way). In short: to turn on the Artifact rotate it sideways and spend a point of Sanity. This takes a turn. To turn off the Artifact flip it face-down. This takes a turn. When the Artifact is on, you are in the Past and may not play new Locations or Travel Events. If you lose the Lamp while you are in the past, you revert to being in the present.