A Broken City, The Climb, and Hiding in Plain Sight are the first quests in Chapter 15, "The Day Midgar Stood Still" in Final Fantasy VII Remake. They take place at the Collapsed Sector 7 Plate. Cloud Strife, Tifa Lockhart, and Barret Wallace head towards the Shinra Building.
Follow Tifa and Barret and then walk down the linear path, and a neighborhood watch member will talk to them. After the dialogue, proceed forward and climb the ladder. Head forward, and a group of byobapolises are found. Aside from character abilities, Wind Materia spells are best against them, though Ice Materia spells are an acceptable substitute. Climb the ladder to the top of a tower, cross the bridge to a second tower and fight two byobapolises, open the chest for a mega-potion, then head back to the first tower and climb the ladder to fight two cerulean drakes. These enemies are likewise weak to wind spells, though aerial attacks are also sufficient. If Enemy Skill Materia is equipped, it is a good opportunity to learn Algid Aura. After defeating them, climb a ladder to proceed.
After climbing, some dialogue will commence. Follow the path forward down a ramp and Tifa will suggest aiming the grappling gun. Aim the to aim the grappling gun, and select to proceed. Following this, a short cutscene commences. Head forward, and a 3-C SOLDIER operators are fought. These enemies are weak to Fire Materia spells, though character abilities are sufficient to defeat them. Proceed forward down the spiraling road, and the grappling gun will e required again. Elite security officers and a guard dog are fought, against which character abilities are ideal. Once defeated, more elite security officers arrive along with a helitrooper are fought; the helitrooper is best defeated with wind spells and aerial attacks. Defeating them will lead to a fight with more elite security officers and elite grenadiers, against which the same tactics apply as against elite security officers. More helitroopers arrive after this in the same battle, and are defeated with the same tactics.
After the battle ends, follow the road left and upwards, leading to the next quest, "The Path to Greater Heights".
Hard mode tips
Prayer Materia should be used to heal while conserving MP. For some enemies early on (namely the cerulean drake and 3-C SOLDIER operators), equipping ice materia paired with Elemental Materia can be helpful for durability. If the elemental materia is matched, this will cause their ice spells to heal, granting a means to heal characters with no need for MP. In early battles, Barret is better off using ranged weapons.
For the longer battle after using the grappling hook, elemental is better paired with fire materia to maximize damage, as ice spells are not used by enemies here. Cloud can use Triple Slash and focus on groups, while Tifa uses with her Unbridled Strength, Starshower, and True Strike abilities. Barret can use melee weapons here, in which case targeting groups of enemies and using Smackdown and Overrun works, though he can also use his ranged weapons to target the helitroopers and target individuals with Overcharge and Maximum Fury. Either way, Barret should use Lifesaver to provide durability for the fight.