Power for the Platform, One Sun Lamp Down, Console Online, Two Sun Lamps Down, and Three Sun Lamps Down are quests in Chapter 6, "Light the Way", in Final Fantasy VII Remake, taking place in the Sector 4 Plate. After reaching Section H of the Sector 4 Plate Interior, Cloud Strife, Barret Wallace, and Tifa Lockhart look for a way to disable the sun lamps in order to secure enough power for the platform and progress to Mako Reactor 5.
To complete this objective, three sun lamps must be deactivated to power the platform.
The first sun lamp closest to the starting platform is located by following a path across a catwalk, the left path across onto another platform, and then traveling upstairs. Grashtrikes are fought here, and once defeated, a catwalk leads across to a sun lamp. Pull the lever on the sun lamp to deactivate it.
Once one is deactivated, Sentry Rays are fought, and best defeated by Barret. Return to the console and the catwalk can be moved. Connecting it to the furthest right path across allows the party to break some boxes and obtain a turbo ether from a treasure chest, while connecting it to the left path across allows the party to proceed across a linear path to the second sun lamp. Along with Sentry Rays, terpsicolts are also fought here; these are fast enemies that use spinning attacks, and are weak to Ice. Use Blizzard (or Blizzara if available) to destroy them quickly, use Barret to shoot from a distance and pressure them, or wait until their spinning attacks end and use physical attacks. Proceed to the second sun lamp, and deactivate it.
Take the ladder down, and then use a moving platform across, where Sentry Gun Prototypes are fought. These enemies are simple machine gun turrets, and can be defeated with character abilities or spells. Once defeated, head left (south on the map) to a lower platform just before the starting position, and use a moving platform to another area, for the third sun lamp. On the first platform, a moogle medal can be obtained in a treasure chest on the south end, adjacent to a ladder, leading down to an area to continue the discovery sidequest "Collapsed Passageway", allowing the Elemental Materia to be obtained. On the main path, follow a linear path until a console is reached, and move a bridge down, then left until a bridge across to another platform is created.
Once crossing the newly-created bridge, a few terpsicolts and Sentry Gun Prototypes are fought; focus on the Sentry Gun Prototypes first as they are quicker to defeat, and then defeat the terpsicolts either with spells, ranged attacks from Barret, or abilities from Tifa and Cloud once they stop spinning. Use the ladder up to the final sun lamp and deactivate it. There is a Mesmeric Armlet around the walkway.
Once the last sun lamp is deactivated, return to the starting point. It is now possible to complete "Inside the Ventilation Fan". To proceed with the main scenario, interact with the console, activating the cargo platform. This will lead to the final quest, "To the Cargo Platform".
Hard mode tips
Although the enemies are more durable, the tactics against them are very similar. In order to conserve MP, it is better to pair Ice Materia with Elemental Materia in order to still exploit the enemies' weakness to it, and character abilities should be relied on more than spells. Against terpsicolts, Barret can use Maximum Fury in place of spells, while Tifa and Cloud focus on ground targets. Time Materia can also be valuable against the grashtrikes' Slow, and if paired with Magnify Materia, Haste can be cast on all party members.