Second Chance Meeting is the first quest in Chapter 8, "Budding Bodyguard", in Final Fantasy VII Remake, taking place in the Sector 5 Slums. After crashing from the Mako Reactor 5, Cloud Strife awakens to find himself in the Sector 5 slums church with Aerith Gainsborough.
Walkthrough
Talk to Aerith after the cutscene, commencing another. After this, a fight begins against two security officers and one elite security officer, which Cloud can deal with quickly with normal attacks and abilities. Once defeated, more arrive.
When all are defeated, Reno is fought. He will dodge Cloud's first attacks, and then use a counterattack. Either dodge his counterattack, and then unleash Cloud's abilities against him, or simply remain in Punisher Mode and wait for him to lunge in with an attack, at which point Cloud will counterattack. If Reno's attacks are dodged successfully, he will be pressured, at which point entering Punisher Mode to unleash Cloud's strong attacks and abilities against him is effective. Reno can also be staggered to deal significant damage.
After losing half of his HP, Reno will jump near the back and toss out electric mines. Avoid being trapped in these or try to destroy them, though otherwise the same tactics apply as before. At range, Reno will throw EM attacks at Cloud, which should be dodged. Reno cannot dodge Limits.
Once Reno is defeated, a cutscene commences, leading to "Escape from the Church".
Hard mode tips
Pairing 
Elemental Materia with 
Fire Materia allows the more durable security officers to be defeated more easily, and Cloud should cast 
Regen often for durability. Counterstance is especially useful when Reno lunges in with attacks, and Blade Burst allows him to be attacked while remaining at range.
Defeating Reno will grant Cloud The Art of Swordplay Vol. VII.