Are you connecting the laptop to one of LAN ports of WR740 and connect the modem to WAN port of WR740N? There is no direct connection between the laptop and modem, right?

Install via web browser. 1. Log in the web interface. http://www.tp-link.com/en/article/?faqid=87 2. Go to quick setup to install it step by step.

The picture it too small to view it clearly...

Try DMZ to see what happens. How did you access it locally?

About the icon issue, post two different screenshots here. I didn't see it is related to router... What's the brand and Android version of your phone? The version is up to date? Try to set a DNS on...

C7 is not working as a router, right? In this case, to access internet, you must "Allow Guest To Access My Local Network". If you use it as a router, it should not be problem....