STEP 1:

Insert the 3G modem on your PC and disable the SIM PIN code. This is usually found under Tools>>Options.

STEP 2:

Insert the 3G modem on your router. 

STEP 3:

In web browser (IE or Firefox) access the menu page of the router (default IP address is http://192.168.1.1) 

STEP 4:

Go to WAN >> Internet Access  Setup page

STEP 5:

 Enter the following details

  1. APN Name: telstra.bigpond
  2. Enter your PPP username and password
  3. Click [OK] button