You need to set up Outlook Mobile Service first. Also make sure your Outlook is running all the time.
1. Click “Tools” menu in Outlook and click “Options…”
2. On the “Preferences” tab, click “Notifications…”
3. Check “Forward messages that meet all of the selected conditions”
If you need to forward emails to multiple mobile numbers, please enter those number into “forward to mobile numbers” field and use “;” to separate them.