Here I am going tell you how you can connect D'Link router to mobile hotspot. For connecting you need some basic things like.
After this Now you connect your computer with mobile hotspot via Dlink 2750u wifi modem
Step 1: First you just have to do Unplug the Power to your Cable/DSL Internet Modem
Step 2: Connect an Ethernet cable from your computer/laptop to a LAN port (Port 1,2,3 or 4) on your router
Step 3: Connect your Cable/DSL modem to the Internet Port on your router
Step 4: Power on both the router and your Internet Cable/DSL Modem
Step 5: Open your web browser and enter https://dlinkrouter or https://dlinkrouter.local or https://192.168.0.1 into the address bar and connect d'link router to mobile hotspot.