On this page of our NieR Automata guide you will find a walkthrough describing the unique events in Chapter 2of Route B, during which you play as 9S. The walkthrough lists all of Route B's new content that appears in the City Ruins and the Resistance Camp.
Route B's Chapter 2 is very similar to Chapter 2 in Route A. The only information on this page are differences and new features you'll encounter while playing through Route B. Remaining info about this chapter and its main objectives can be found by reading Route A's Chapter 2 walkthrough.
Just like in Route A, this chapter begins with a flight sequence during which the player uses the Flight Suit.
Once you reach the City Ruins you can focus on your main objectives or on the unique exploration options available to 9S. The aforementioned options consist of locating and opening locked chests. 2B couldn't access them, but 9S can open them by using his hacking abilities. The first locked chest can be found on the landing site (shown on the picture above). It contains a unique Phoenix Sword weapon. The use of 9S' unique abilities is described in more detail on the Hacking page.
All of the Access Points in the ruins are available from start. However, you must reach Chapter 5 to unlock fast travel once again.
Just like in Route A, your first objective in the Resistance Camp is finding Anemone. After meeting her, you must talk to several specific resistance members and once again finish the short quests they give you. You should expect the quest-related machines to have higher experience levels than their Route A counterparts. Nevertheless, 9S is stronger than 2B which means the overall combat difficulty should remain unchanged.
Inside the Resistance Camp you can look for formerly unopenable chests. The one in the picture is hidden in the corner left to the Access Point. Hacking it open rewards the player with a unique Type-4O Fists weapon.
Just like in Route A, Anemone will send you out into the desert. Your visit there is part of Chapter 3.