You can easily set up conference calling using Twilio by creating a conference room with the verb `Conference` in your Twilio call flow, and then dialing into that room from any phone number. You can also use the `waitUrl` attribute to play audio while participants wait for the conference to start. Additionally, you can route incoming calls to different conference rooms based on the caller's phone number using a conditional statement. To add an extra layer of security, you can require callers to enter a PIN before joining the conference. Twilio also provides a REST API that allows you to initiate conference calls programmatically, and you can use this API to call multiple participants at once. You can also get a list of active conferences using the `Conferences` endpoint, and fine-grained control over individual participants by using the `Participants` endpoint. With these features, you can build your own conference calling solution or extend existing ones.