To link IVR interactions with inbound calls using Flex Insights, developers can create an IVR Task, assign it to a "Nobody" TaskQueue and Workflow, and then use Twilio Studio and Functions to set up custom attributes and metrics. The IVR task is linked to the inbound call by overriding the conversation_id attribute, which is generated by default by Flex Insights. This allows for visibility into customer interactions with the IVR, enabling developers to track abandoned calls, measure queue time, and create custom reports that consider IVR segments. By using Twilio Flex, developers can build a contact center that provides a good customer experience and reduces agent handling time, while also gaining insights into customer behavior and preferences.