Download or clone the repository as mentioned above but do not open it in Unity. Use your file-browser to navigate into the Folder "…/vuframe-plugin-unity-master/Assets/" and copy the folder "Vuframe" into the Assets folder of your project.
If you are using another Version than Unity 4.7.2, Unity will prompt you a dialog, asking to upgrade the project. Proceed and upgrade it. Next Unity will ask you for an API update, proceed as well, by clicking on "I Made a Backup. Go Ahead!“. Finally, Unity will give you the message that a Layout could not be opened. Click on "Load Default" Layout. Congratulation, you are in.