Task: Creating an API endpoint

n8n workflow JSON:
{"meta":{"instanceId":"8c8c5237b8e37b006a7adce87f4369350c58e41f3ca9de16196d3197f69eabcd"},"nodes":[{"id":"f80aceed-b676-42aa-bf25-f7a44408b1bc","name":"Webhook","type":"n8n-nodes-base.webhook","position":[375,115],"webhookId":"6f7b288e-1efe-4504-a6fd-660931327269","parameters":{"path":"6f7b288e-1efe-4504-a6fd-660931327269","options":{},"responseMode":"responseNode"},"typeVersion":1},{"id":"3b9ec913-0bbe-4906-bf8e-da352b556655","name":"Note1","type":"n8n-nodes-base.stickyNote","position":[355,-25],"parameters":{"width":600,"height":280,"content":"## Create a simple API endpoint\n\nIn this workflow we show how to create a simple API endpoint with `Webhook` and `Respond to Webhook` nodes\n\n"},"typeVersion":1},{"id":"9c36dae5-0700-450c-9739-e9f3eff31bfe","name":"Respond to Webhook","type":"n8n-nodes-base.respondToWebhook","position":[815,115],"parameters":{"options":{},"respondWith":"text","responseBody":"=The URL of the Google search query for the term \"{{$node[\"Webhook\"].json[\"query\"][\"first_name\"]}} {{$node[\"Webhook\"].json[\"query\"][\"last_name\"]}}\" is: {{$json[\"product\"]}}"},"typeVersion":1},{"id":"5a228fcb-78b9-4a28-95d2-d7c9fdf1d4ea","name":"Create URL string","type":"n8n-nodes-base.set","position":[595,115],"parameters":{"values":{"string":[{"name":"product","value":"=https://www.google.com/search?q={{$json[\"query\"][\"first_name\"]}}+{{$json[\"query\"][\"last_name\"]}}"}]},"options":{},"keepOnlySet":true},"typeVersion":1},{"id":"e7971820-45a8-4dc8-ba4c-b3220d65307a","name":"Note3","type":"n8n-nodes-base.stickyNote","position":[355,275],"parameters":{"width":600,"height":220,"content":"### How to use it\n1. Execute the workflow so that the webhook starts listening\n2. Make a test request by pasting, **in a new browser tab**, the test URL from the `Webhook` node and appending the following test at the end `?first_name=bob&last_name=dylan`\n\nYou will receive the following output in the new tab `The URL of the Google search query for the term \"bob dylan\" is: https://www.google.com/search?q=bob+dylan`\n\n"},"typeVersion":1}],"connections":{"Webhook":{"main":[[{"node":"Create URL string","type":"main","index":0}]]},"Create URL string":{"main":[[{"node":"Respond to Webhook","type":"main","index":0}]]}}}