If you want to check, how many Candidates your Vendor has submitted in the system. You need to go to the Candidates screen from the left hand side menu option.

In the Candidates Module, simply filter the Candidates by the Owner of the profiles, from the left vertical filter options.

You can also see the Owner name on the Candidate panel.

Search Candidate Submitted by Vendor

To search Candidates which are submitted by the Vendors into the system. For that you need to go to the Advance Search option, which is on the right hand side of the Candidates screen. 

In Advance Seach you need to click on to the Other Search Tab.

Now you need to scroll down, and choose the Venodr Name or Vendor Contact to search the Candiates submitted by Vendor.