To use SimpleKPI integration in n8n, start by adding the HTTP Request node to your workflow canvas and authenticate it using a generic authentication method. Once connected, you can make custom API calls to SimpleKPI to query the data you need using the URLs you provide, for example: to create records in SimpleKPI via n8n, configure your HTTP Request node with a POST method and the appropriate URL for creating an entry, including the necessary JSON body with your KPI data. For updating records, use the PUT method along with the specific record ID in the URL and updated data in the body. To retrieve data, set your node to GET and target the appropriate endpoint, allowing you to seamlessly integrate and manipulate your KPI data within your workflows.