Click on the vm_web.exe from the Files in the download section. This will start the installation of Windows Phone Developer Tools Beta and install the necessary components on your machine.
For an offline installation, download WPDTBeta_en.iso and create your media and run setup.exe to install Windows Phone Developer Tools Beta.
Note: There are known issues during the uninstallation of the CTP version of the Windows Phone Developer Tools. Please read this
blog article for more information and steps to resolution.
Please review the Release Notes for additional details before running setup.