DevOps: Books Videos Materials

Books

Mastering Salesforce DevOps -  link

The DevOps Handbook - link

Pro Git (free) - link

Video

Introduction: The State of Salesforce DevOps - link

Discover Salesforce, DevOps and Copado CI/CD automations - link

Azure DevOps with Salesforce - link

Trailhead SF

You need to study the following Trails:

Admin Beginner - link

User Management - link

Quick Start: Salesforce DX - link

Quick Start: Visual Studio Code for Salesforce Development - link

Package Development Model - link

Unlocked Packages for Customers - link

Data Security - link

Build Apex Coding Skills - link

Articles (here you will find many answers on salesforce)
Salesforce Developers Blog - link