First, you need to install Webcam Profile (for CTA5) --or-- Motion LIVE 2D and the Face3D Profile (for CTA4). Note that Face3D Profile is known as Webcam Profile in CTA5.

After installing the Webcam Profile (CTA5) / Face3D Profile (CTA4), you will see the Face3D Tracker icon on your desktop.

Follow the below steps to start the program:
1) Open Cartoon Animator 5 / 4
2) Open the Face3D Tracker (Cartoon Animator 5) / Face3D Tracker (CTA4)
3) Open Motion LIVE 2D in Cartoon Animator 5 / 4

Then refer to the below instructions to start your first facial capture project:
https://manual.reallusion.com/motion-live-2d/cta/facial-mocap/workflow-for-motion-live-face.htm