On this page of the guide to Watch Dogs Legion you will learn how to pass the first mission of the chapter Albion's missions, Gap in the Armor. To start this mission, select task tracking in your mission menu.
When you finish the Kelley chapter, you'll be able to choose between Albion chapter missions and 404. Choosing Albion missions, you will need to appear in the DedSec hideout, and then in the Battlebridge Basin. Locate the box you need to hack. It is located on the roof of the building, where you will be guided by a marker on the map.
The easiest way is to use a transport drone to get there. If you don't have the opportunity, there are cranes on the other side of the building that will take you to the very top.
Once you're on the roof, hack the electronic box. Once you've done that, you'll take control of the camera inside the apartment.
Turns out the inside of the building you used the cameras to get into is rigged with explosives. The solution will be a simple puzzle. Switch nodes in such a way as to unlock more points.
For a better view, switch to the camera on the right. Next to the wheel that shows an unlock option, you must follow the blue line in the directions in which the arrows are pointing. Remember that if you unlock a given point, you can twist the previous one to guide all the blue nodes to the bomb-defusing mechanism.
When you disarm the bombs, go to the next marker, which is located on the other side.
Then a longer cutscene will start. When it's finished, Albion will appear on the spot and chase you. You must lose their pursuit. However, this does not mean that you will have to flee from them across the city by car. This is one of the options, but it is best to hide somewhere between the buildings. For a short time, enemies will be looking for you all the time, but if after a while they have zero clues where you're hiding, they will begin to lose interest, so a blue tracking panel will appear on the left side of the interface. Once the blue panel is gone, you'll be safe and complete the mission.