First you need a disguise and a keycard (unless you are a hacker) Go to the back of the bank and disable the camera (its the dumpster camera) wait for the guard to approach then equip your gun and press v next to the guard, take the guard out and then put the guard in a body bag, obtain the keycard if possible (if not disable the downstairs camera and repeat above) move the body next to the dumpster and get the disguise, then toss it in the dumpster. Your basic loadout entails a pistol (ensure its concealed and suppressed) and a keycard, don't need a drill yet. Now, move to the second floor and go to the door right next to the archives area and take out the operator, if you are a hacker disable the cameras. From there, start taking out one by one the employees in the area, Ensure the employee is towards the back so that you are out of sight, when the manager enters, ensure only the manager can see you, then take the manager hostage and bring the manager into the camera room. Get the keycard and interrogate the manager, from there you need to get into the archives room for the box number and to disable the sensors. Once you get the blueprints, make your way down to the vault, kill all the guards in the basement and camera room and disable the cameras You will also need to drill into the sensor (this is where you need a drill at this point) from there, get the package and you are good to go

When killing the employees in the second room, ensure you put the body bags in the camera room