Open your web browser, navigate to Google.com, enter in optimistic concurrency ado.net and then click the Search button. Being a beginner means that you don't know how to program, not that you don't know how to use a computer or the web. When someone tells you what to look for, look for it.
That said, optimistic concurrency is a way to handle data conflicts in a multi-user environment. It is not an architecture for distributed applications. For that you will need to create multiple projects. You will presumably want to create a web service and a client application at least. The web service would be created using WCF and it would connect to the database directly. Your multiple client apps would then connect to that service.
You could also create a web site instead of a Windows client. The web site could connect directly to the database or it could connect to the web service.