For an outside installation, the soil around your foundation must be excavated to expose the footing at each pier location. For an inside installation, a section of your slab floor will need to be removed to expose the footing. The slab is restored after the installation.
A section of the footing will be cut away so that the steel bracket connected to the pier will support the wall directly.
This approach will provide more effective support than lifting the section of the footing that extends beyond the walls.