Waldo integration with Bitrise requires you only to add the Upload to Waldo step to your workflow.

First, create a new simulator build for your app. When you use the Xcode build for simulator step to build your app, output variables are generated that you can then use as input to the Upload to Waldo step to find and upload the generated app.

workflows:
  primary:
    steps:
    #...
    - xcode-build-for-simulator:
        inputs:
        - xcodebuild_options: CODE_SIGNING_ALLOWED=YES
    - waldo-upload:
        inputs:
        - build_path: $BITRISE_APP_DIR_PATH
        - upload_token: $WALDO_UPLOAD_TOKEN     # from your secrets
    #...

Note: The value you supply to the upload_token input should be specified as a “secret” environment variable by going to the Secrets tab in the Bitrise Workflow Editor and assigning your upload token to WALDO_UPLOAD_TOKEN. (Your app’s upload token is 0123456789abcdef0123456789abcdef.)