Installing OSTimer extension with Joomla's built-in extensions installer is easy.
- In your Joomla control panel, go to Extensions > Manage:
You will see Extensions: Install administrative page.
- Under the Upload Package File tab, click the Or browse for file green button:
- In the "Open File"> box, find the Joomlashack extension you need to install. Click on the file name twice.
- Everything being well, you should see a successful installation messages on a light green background: