The article guides users through the process of building an application that enables users to make phone calls directly from a web browser using Vue.js and In-App Voice with Vonage. The application uses the Vonage Client SDK for JavaScript, requires a server setup with Express.js to generate a User JWT, and utilizes Ngrok to create a local tunnel for communication between the browser and the Nexmo platform. After setting up the client-side functionality, users can enter a valid phone number, click the call button, and initiate an outbound call from their web browser. The application also supports receiving inbound calls using In-App Voice in Developer Preview.