Folder structure
I advise against keeping your frontend and backend code in the same code repository. Using the same repository leads to bizarre dependencies when you need to enable Continuous Integration or deploy your code to production. In order to get an integrated development experience with the ability to quickly switch between repositories, you can use IDE features, such as VS Code Workspace, to open multiple repositories under the same tree-structure at once.
If you must use a single repository, create separate folders for backend code and frontend code, named server and web-app, respectively. The benefit of doing this at a minimum is great, because team members can start working on either the frontend or the backend without stepping over each other's toes.
Follow the instructions in the next two sections to set up your application correctly. If you already have a robust development directory setup and you're a Git pro, then skip over to the Generate Your Angular Application section.