Is there anyone can show me how tfind the simple instruction of using MacBook by free?

There's some free 'user guides' online to check.

1. 2020+ M1 Apple Silicon MacBook Air 13-inch
2. 2020 Intel-based MacBook Air 13-inch

MacBook Air (M1, 2020)

Colors: Space gray, gold, silver

Model Identifier: MacBookAir10,1

Part Numbers: MGN63xx/A, MGN93xx/A, MGND3xx/A, MGN73xx/A, MGNA3xx/A, MGNE3xx/A

Tech Specs: MacBook Air (M1, 2020)

User Guide: MacBook Air (M1, 2020)

MacBook Air (Retina, 13-inch, 2020)

Colors: Space gray, gold, silver

Model Identifier: MacBookAir9,1

Part Numbers: MVH22xx/A, MVH42xx/A, MVH52xx/A, MWTJ2xx/A, MWTK2xx/A, MWTL2xx/A

Tech Specs: MacBook Air (Retina, 13-inch, 2020)

User Guide: MacBook Air (Retina, 13-inch, 2020)

{..above from: • Identify your MacBook Air model - Apple Support..}

• Welcome to MacBook Air Essentials - Apple Support

https://support.apple.com/guide/macbook-air/welcome/mac

• MacBook Air - Official Apple Support

https://support.apple.com/mac/macbook-air

• MacBook Air Essentials - (Table of Contents) - Apple Support

https://support.apple.com/guide/macbook-air/toc

• macOS User Guide - Apple Support (MB/Air)

https://support.apple.com/guide/macbook-air/macos-user-guide-apdfdad69354/mac

• MacBook Air - Technical Specifications | Apple Silicon M1 (2020+)

https://www.apple.com/macbook-air/specs/

• Find the manual for your Mac - Apple Support

https://support.apple.com/guide/system-information/find-the-manual-for-your-mac-syspr35535/mac

• Contact Apple for support and service - Apple Support

https://support.apple.com/en-us/HT201232

• Apple Repair and Repair Status Check - Official Apple Support

https://support.apple.com/repair

• Genius Bar Reservation and Apple Support Options - Apple

https://www.apple.com/retail/geniusbar/