Install Blackberry Themes

Download the themes. If they are archived (most likely) extract them in a folder;
2. Open Blackberry Desktop Manager and connect your Blackberry;
3. Enter the Application loader, click Next;
4. Hit the Add button, search the folder where you have the themes, select Themes.alx then click Next;
5. Click Next and wait for the program to load all the files;
6. Enjoy your newly installed themes.






Source : http://mwolk.com/blog/install-blackberry-themes