Crisis Core: Final Fantasy VII/06: Protect Your Honor

This chapter starts at Costa del Sol.

Costa del Sol
After some cutscenes and fights, you will need to go to Junon.

Junon
In Reunion, you'll get access to a new feature called Buster Sword Proficiency, it allows you to perform a Battle Stance by pressing psx: X + psx: S / +.

Lower Junon - Level 3
At the end of the road, there is a chest containing a Bronze Armlet. Just continue.

Lower Junon - Level 6
After a cutscene and a fight against another Genesis copy, you will need to go forward, you'll receive another mail from Kunsel in the way. Just continue forward.

Central Tunnel - Level 6
You'll get a cutscene and then a boss fight.

After the fight, another cutscene, and then you need to continue forward, grabbing two mails in the way.