Analyze feedback and send a message on Mattermost

This workflow analyzes the sentiments of the feedback provided by users and sends them to a Mattermost channel. Typeform Trigger node: Whenever a user submits a response to the Typeform, the Typeform Trigger node will trigger the workflow. The node returns the response that the user has submitted in the form. Google Cloud Natural Language node: This node analyses the sentiment of the response the user has provided and gives a score. IF node: The IF node uses the score provided by the Google Cloud Natural Language node and checks if the score is negative (smaller than 0). If the score is negative we get the result as True, otherwise False. Mattermost node: If the score is negative, the IF nod

Help me set up the n8n workflow "Analyze feedback and send a message on Mattermost" (https://n8n.io/workflows/786). It uses: Mattermost, Google Cloud Natural Language. Import the template JSON into my n8n instance, list every credential I need to create, and walk me through testing it.