While the Starter plan allows you to use your own API keys for data enrichment, the HTTP API feature is only available with the Explorer plan. Unfortunately, you won't be able to implement the HTTP API lesson on the Starter plan.
However, you can still learn about the concept. We have resources available in Clay University that explain HTTP API usage. If you need further assistance or have specific questions about the lesson, please let us know. We're here to help you understand the concept, even if you can't implement it yet.