Objective: introduction to timeline
Timeline is included in the Cinemachine package, but can be use independently. Timeline is a none linear editor that can be used to sequence animation. Different from key animation, to use timeline, first we need to create a new sequence.

To access timeline window, go to Window > Sequencing > Timeline.
Objective: create Camera driven by animation states.
State Driven Camera let you create virtual cameras driven by the animation state of the object. One of the example of using state driven camera would be in a FPS game, depending if the character is aiming or idle, the camera switch between close up and a wide shot.
First I prepared 2 animation that switch can switch with a bool(article of creating animation states). ps idle was spelt wrong :P

Next, create a CM StateDrivenCamera, and create 2 different virtual cameras for the states. Include the Animated Target, and connect the states to the cameras.
Objective: create clear shot camera
Clear shot camera is camera control based on visibility. I put in some walls that can block the vision in some area, and set up 2 virtual cameras as below.

Create CM Clear shot camera and set the virtual cameras as children. make sure the 2 cameras are aiming at the character and added cinemachine collider extension.
Objective: using Blend List Camera to create security Camera
Blend List Camera let you to choreograph and switch between the virtual camera that are child elements under Blend List Camera
Create the camera under Cinemachine drop down, and you can add more cameras from drop down or duplicating existed one. The list in the middle let you plane how the camera switching between each others. and check loop for it to repeat on its own.

for the security camera, i have 2 cameras, they look at different directions. I can animate them so it switch in between 2 positions, and pause a bit before switching again.