Unable to see mesh PointCloud Viewer

Hi,

I am new to unity. I have licence of unity. I have downloaded “PointCloud Viewer & tools" as well. I am unable to view the dragon sample or other sample provided . After 2 day efforts i can only see a single dot. I don't know whats the issue. Please resolve my issue. I have tried all options explained in manual. But unable to figure it. Your prompt reply will be appreciated.

Thanks Razia