1. Place the camera
The SecurityCamera actor is available in the Class browser under Decoration -> DeusExDecoration -> ElectronicDevices -> HackableDevices. Place your camera(s) in an appropriate place, typically on a wall or ceiling, perhaps pointing toward an important door or room.
At this point, you'll have a stationary, active camera that will trigger an alarm, is not tied to a security console, is hackable, and has a hack strength of 20%. If that's what you want, then you're done!
2. Set the camera's general properties (optional)
The "SecurityCamera" properties are pretty straightforward. Right-click on your camera and select Properties and then expand the SecurityCamera category. These are covered in the EditorDocumentation.doc file, but what the hey:
3. Set the camera's "hackability" properties (optional)
The security camera, as with any "hackable device", can be set up so that a Multitool can bypass it. To set whether or not the camera is hackable as well as its strength, expand the HackableDevices category. As you might guess, set bHackable to True to allow the camera to be bypassed using Multitools. Set the hackStrength to the strength percentage (0.20 means 20%). A value of 20% means that a player untrained in electronics will need to use two Multitools in order to bypass the camera.
4. Associate the camera with a security console (optional)
If you would like the camera to be accessible via a security console, give it a Tag name in its Events properties by right-clicking on it and selecting Properties. Expand the Events category, and fill in the Tag value.
Now select the security console that you'd like to control your camera and pull up its Properties sheet. Expand ComputerSecurity -> Views. These correspond to the three video monitors that the player sees in the game when accessing a security console. Type in the tag values of the camera(s) you want to assign in the cameraTag fields. The player will see static for any of these that you leave blank.
Fill in a descriptive name (usually the type of
room the camera is in) in the titleString field. The player will see this under
the appropriate video monitor.