Here’s a list of Silhouette training resources.
Silhouette User Guide
Documents every feature and included tutorials.
Paid Training - Boris FX
Mastering Silhouette
Digital Beauty Basics in Silhouette
Paid Training - fxphd
Introduction to Silhouette and Roto
Introduction to Silhouette and Paint, Part 1
Introduction to Silhouette and Paint, Part 2
Paid Training - LinkedIn Learning
Learning Silhouette
Free Silhouette Videos - Boris FX
Complex Wire Remove with Silhouette and Mocha
Short Videos by Subject
Complete List of Videos
Free Silhouette Videos - YouTube
VFX World
madlookz VFX
Compositing Resources
Digital Compositing for Film and Video
by Steve Wright
The Art and Science of Digital Compositing: Techniques for Visual Effects, Animation and Motion Graphics
by Ron Brinkmann