how do I run c++ on my MacBook Air m1 in visual studio

What’s your central goal here? Learning VS Code and C++, or Xcode and C++, or C++ at the command line?

…if learning about C++ on macOS, you can use the (free) Xcode IDE, and which fully supports C++.

Xcode IDE can be installed from the Mac App Store.

…If you want help with learning or using a third-party IDE such as Microsoft VS Code, I’d suggest checking with the vendor. In this case, Microsoft has discussion forums and documentation available for VS code:

https://code.visualstudio.com/docs/cpp/config-clang-mac

…If you just want focus on and use C++ with no IDE, the command line tools and a text editor and clang will work.

The command-line tools by launching Terminal app and issuing the command:

xcode-select --install

Related: https://www.macobserver.com/analysis/5-ways-to-write-c-code-on-your-mac/

See also: Microsoft's C++ programming with Visual Studio Code

and Mr. Hoffman has already provided the link for using the clang/clang++ compiler with VSC.