I have downloaded a trial version and installed both Designer and Server. Now I am trying to add Nevron chart to my report but dotn see how. Can someone please help?

Thanks 

Hello Mark,
Once you install the Nevron Vision for SSRS Designer installation package on your report development machine, you should be able to see the Nevron custom report items (CRIs) in the Visual Studio toolbox (BIDS or SSDT-BI) like the standard SSRS report items.

You can check the following introduction video: Nevron Chart for SSRS Getting Started

Can you please let us know if what is your environment: version of SQL Server Reporting Services and version of Visual Studio.

Best Regards,
Nevron Support Team