Backstage Pass

Head to the marked location. There are several ways of dealing with the gunment below without breaking a sweat. Some of the guards are carrying explosives that you can remotely detonate while some are standing beside hazardous objects. From there, you can enter the restricted area and take them out one by one. You can do this stealthily if you have a silenced weapon. Otherwise, you have to move from cover to cover and sneak behind them to take them out using your baton.

Continue taking out the guards until you find the one carrying the code. Hack the code and wipe them all out if you want. Just make sure to prioritize taking out the guard that can call in reinforcements. After getting the key, head to the security router and hack it.

Once you're in the router, you have to do a series of routing the data connection. The last one has a red marker. This means that after activating it, you have a few seconds to complete the circuit before you get detected.

Once you're able to break in, you can hack a few of the servers to get some video leaks. Finally, unlock the ctOS system to gain access to the district and complete the mission.