I played Halo 3 a while ago but I forget how they got to the ark, does anyone know?
The huge structure the covenant was excavating from underneath Africa created a portal to the Ark when it was activated.
So did high charity also go through the portal or was that the ship that crashed into earth?
Oh… you meant how did High Charity arrive!
The Gravemind, with its infinite Precursor knowledge, activated the city’s slipspace drives and appeared right on top of the Ark in one of the last cutscenes of the level “The Covenant.”