Since a cable modem doesn't have router function so that it only allows one device to access internet, in your case, you need to configure the TL-MR3020 in router mode in order to share wifi network. So switch the hardware mode switch to 3G/4G, then connect your computer to MR3020's wifi, login to the router's web management page and choose WAN only as "internet access", choose "Dynamic IP" as WAN connection type and finish the reset. Hope this helps.

Thanks for your reply. I have tried the way you suggested but it is still the same and even the netbook cannnot connect to the WIFI router right now. The problem is that the IP address is same as the router, i.e. 192.168.0.254 and the error message "The DNS server is not responding". It seems that the Dynamic IP is not working properly.

Does anyone use TL MR3020 as WIFI router for home boradband before?
Do I need to clone the MAC during configurating the router?
What is the possible missing link here?

Thanks,