Generate and Auto-Evaluate Facebook Ad Headlines using GPT-4o-mini

Generate and Auto-Evaluate Facebook Ad Headlines using GPT-4o-mini Built with n8n + OpenAI This workflow captures a product description, generates ad headlines, evaluates them with custom criteria, decides whether another draft is needed, and finally sends the best version via Gmail. ⚡ Section 1: Capture the Brief & Build the Prompt 📝 FormTrigger\CopywritingBrief → A simple form asks: “What is your product about?” ⚙️ Set\PromptForHeadline → Prepares the input by appending the instruction: “Write a Facebook ad headline for this product:” Benefit: Ensures consistent, structured prompts so the AI receives clear context every time. ✍️ Section 2: Draft the Headline 💬 LLM\HeadlineWriterModel → G

Help me set up the n8n workflow "Generate and Auto-Evaluate Facebook Ad Headlines using GPT-4o-mini" (https://n8n.io/workflows/6081). It uses: Gmail, AI Agent, OpenAI Chat Model. Import the template JSON into my n8n instance, list every credential I need to create, and walk me through testing it.