Whenever I connect my note 3 sm-n900 to my laptop, it doesn't connect and also the usb icon doesn't appear on my notification panel. My Android version is 5.0
i have experienced the same problem in the past. Here is my Guide:
Navigate to Settings > About Phone > scroll to the bottom > tap Build number seven (7) times. You'll get a short pop-up in the lower area of your display saying that you're now a developer. 2. Go back and now access the Developer options menu, check 'USB debugging' and click OK on the prompt.
Good luck and i hope i'm helpfull
do you have installed drivers? you can find it here http://downloadcenter.samsung.com/content/SW/201410/20141017131240597/SAMSUNG_USB_Driver_for_Mobile_Phones.exe also is your phone charing when is connected? try to install drivers,restart phone(reboot) and connect it. If that dont work try to use other usb cabble