Open a new project in Flash Builder. Select "File" then "New" and "Flex Project." In the "Create a Flex project" window, name the project, select a project location, select an application type, choose a Flex SDK version and pick the Application server type. Click "Next" at the bottom of the window.
Verify your server configuration and click "Validate Configuration," then click "Finish" to complete the project creation. In the main window, you will see the name of your file as Name.xml. Switch to "Design" view by clicking the tab. Now you can start coding to build your application.
Open the "Components" menu on the left-hand side and open the "Controls" folder. Select the "Label" control, hold down your mouse button, and then drag it to the "Design" view area. When you double-click this component, you can add any new text and change the font attributes.
Switch to "Source" view in order to begin your MXML coding. Switch to the "Design" view to view your application while you're working on it. Different controls from the "Controls" menu are automatically coded into the "Source" view when you drag them to the "Design" area.
Save your file and click the "Run" green arrow button at the top to run your application.