The instructions are here: http://www.gl-inet.com/download/mifi/
Some common problems:
Make sure the module support your SP
When you install the SIM card, be gently. Don’t twist and bend the pins. Please check the picture.
Read the "quick start guide here: http://www.gl-inet.com/download/mifi/
When you have problem, post your problem here. We will try our best to help!