Depending on whether multiple applications will use the same PowerServer solution or each application will use its own PowerServer solution, you can choose to create a new C# solution or use an existing solution. If you want one PowerServer solution to be used by all applications, you can choose an existing solution; and then deploy the app (as well as the others) to this solution. If you re-deploy an app to an existing solution, the application data models and ESQLs will get updated in the solution, and if you deploy a new app to an existing solution, the application data models and ESQLs will be added to the existing solution.
If you plan to host the PowerServer Web APIs on the cloud server (in a docker container, for example), you probably might want to use one solution for all applications. In this case, you can select an existing solution and deploy the applications to the same solution.
However, if you plan to host the PowerServer Web APIs in the IIS server, as IIS allows you to create multiple websites in a single server, you can host the Web APIs on its own dedicated website, and each application has its own dedicated Web APIs. This means, if you have more than one application, each application and each Web APIs can be hosted on its own dedicated website. In this case, you can select to create a new solution for each application.
For configuring the solution for the PowerServer project, refer to Configure the solution basics for details.
