Use the Angular project template with ASP.NET Core

Create a new app

dotnet new angular -o my-new-app
cd my-new-app

Add pages, images, styles, modules, etc.

The ClientApp directory contains a standard Angular CLI app

Run ng commands

remove package-lock.json then :

cd ClientApp
npm install

Install npm packages

cd ClientApp
npm install --save <package_name>

Run “ng serve” independently

cd ClientApp
npm start

Use npm start to launch the Angular CLI development server, not ng serve, so that the configuration in package.json is respected. To pass additional parameters to the Angular CLI server, add them to the relevant scripts line in your package.json file.

In your Startup class, replace the spa.UseAngularCliServer invocation with the following:

spa.UseProxyToSpaDevelopmentServer("http://localhost:4200");

References
https://docs.microsoft.com/en-us/aspnet/core/client-side/spa/angular?view=aspnetcore-6.0&tabs=visual-studio