anAtomic depends on Eevee viewport rendering to be enabled. Hold Z and drag to Material Preview or Rendered view:

As an artist myself, I built this tool primarily to aid other artists who want to learn and reference comprehensive facial anatomy in a 3-dimensional format.

I omitted the deeper internal anatomy because I focused on structures that most directly affect the external shape of the head. Since the spine, mouth cavity, brain and some muscles (like the platysma) don't notably affect the external shape of the head, they're not included.

Lex's shaders require certain 2.81 nodes to render properly. If you're experiencing black in the eyes or anything that's visually different from the images/video on the product page, make sure you're opening the file with 2.81 and not 2.80.

No you don't need to be proficient with Blender to use anAtomic fully. Just think of Blender as the platform for interacting with the model. Blender's free to download and easy to install on any OS (just unzip directory to any folder and launch the app within). Open the anAtomic .blend file, navigate with MMB (orbit), SHIFT + MMB (pan), and CTRL + MMB (zoom/dolly) and click the buttons on the right to navigate anatomical layers.