Head for the Pillar is the first quest in Chapter 12, "Fight for Survival", in Final Fantasy VII Remake, taking place in the Sector 7 Slums. After traveling through the train graveyard, Cloud Strife, Aerith Gainsborough, and Tifa Lockhart return to stop the Sector 7 plate falling.
Walkthrough[]
Mysterious spectres appear.
Follow Tifa as she sprints towards the slums. After catching up with her, a cutscene commences, and mysterious spectre enemies, as well as an enigmatic spectre enemy, are fought. Destroy one of the mysterious spectres to pressure the enigmatic spectre, and then use magic spells or abilities against it. A few spells can stagger it, at which point more severe damage can be done. While staggered, lay into it with more spells, and use Tifa's Unbridled Strength martial techniques against it.
After defeating the spectres, run forward towards the pillar for another cutscene. Tifa and Aerith leave the party. Cloud should equip 
Fire Materia to take advantage of the enemies' weakness to it. Run forward as Cloud, use the bench, then head up the stairs on the right to the Pillar 2F. Move past the boxes, and fight a group of Sentry Guns and elite security officers, which can be defeated with spells or Cloud's abilities swiftly. Following this, head up the stairs to 3F, where elite riot troopers are fought, best defeated by casting spells, though Cloud can alternatively wait for them to attack and then dodge and use his own attacks. Two orbs of gravity can be obtained in the chest at the back, after which, head up to the stairs for a cutscene on floor 4F. After Biggs asks Cloud not to let the battle be for nothing, the player can select "I won't" or "What about you?"; either option progresses the cutscene.
After the cutscene, head to the back and use a ladder to floor 5F, and two helitroopers appear; these are flying enemies with strong melee attacks that are weak to both fire and 
Wind, and Cloud is best to either cast spells against them or use aerial attacks to stagger them. Dodging their melee swipe will pressure them, providing Cloud a good opportunity to retaliate with a spell, though Cloud can also counter it in Punisher Mode. Once they are defeated, head up the stairs to 6F, where a helitrooper with two elite security officers are fought; the same tactics apply as before, casting fire spells is the best tactic against them. After this, head up a ladder and up further stairs to 7F, where a cutscene commences. When the cutscene finishes, the next quest, "Evacuation Orders", starts.
Hard mode tips[]
Against the spectres, as before, focus on the smaller mysterious spectres to stagger the larger one. The outcome is the same regardless; deal damage to the enigmatic spectre until it leaves on its own in a cutscene. To speed things up, simply work to build its stagger gauge. If spells are used, use Lightning Materia spells as they are guaranteed to hit, and only use spells as Aerith, whose MP is irrelevant for this chapter.
As Cloud fights through the Shinra soldiers across the pillars, it is best to conserve MP and focus solely on physical damage. Cloud can pair 
Elemental Materia with fire materia, and use the 
Hardedge to optimize physical damage output, as well as to grant him the Bloodsucker passive to heal him without reliance on MP. 
Parry Materia and Steadfast Block Materia are crucial on Cloud, who should use Punisher Mode and rely on counterattacks, and First Strike Materia is helpful.
Cloud can cast 
Regen as an MP-efficient means of healing. Most enemies can be fought using Triple Slash. The elite riot troopers, once fought using spells, can instead be beat using Counterstance. Against helitroopers, Counterstance can be used against both their gunfire and Proton Swipe, though casting Fire may be required.