How do I get useful SQL Server database performance statistics?
You can gather data you need with Data Collector, which is a part of the SQL Server Management Studio (not in all SQL Server editions though), but it’s features are limited and it won’t show you any real-time data.

It seems you need an ad-hoc solution and, if that is the case, it’s better to use some 3rd party monitoring solutions to gather data and get the job done during free trial. All these tools are great and are offering fully functional free trials:

ApexSQL Monitor

Idera SQL Diagnostic Manager

Redgate SQL Monitor

SQL Sentry