How to select Development team for iOS app created in Flutter

I am trying to deploy an iOS app to Device using Google's Flutter, but I get this error on the command line:

Building an iOS app requires a selected Development Team with a Provisioning Profile
Please ensure that a Development Team is selected by:
  1- Opening the Flutter project's Xcode target with
       open ios/Runner.xcworkspace
  2- Select the 'Runner' project in the navigator then the 'Runner' target
     in the project settings
  3- In the 'General' tab, make sure a 'Development Team' is selected
For more information, please visit:
  https://flutter.io/setup/#deploy-to-ios-devices
Or run on an iOS simulator

Where and how do I do this? There is no "ios/Runner.xcworkspace" in the project. I know the installed Certificates and Provisioning profile work on my Mac, because I created and installed an app on my iOS device using Appcelerator, and it found everything I needed, and ran perfectly on device.

Solution

Select Runner, and navigate to Signing & Capabilities, under Signing, check Automatically manage signing, after that choose a Team from the list, and you're done.