when i plug it it says mtp connected and when i click on it. it doesnt do noting
So when you pull down your notification bar, do you have a notification that says "USB Connected"? If you click that a window should pop up that has a button that says "Connect USB Storage". Hit that and it should mount your internal SD, and your external SD if you have one.
For rooting purposes using Odin, go to Control Panel on your computer, then Device Manager > Universal Serial Bus Controllers. If you see "SAMSUNG Mobile USB Composite Device" listed then you're good to go on the drivers.
If you continue to have problems try a different USB cable. Also try toggling "USB debugging" on your phone on or off to see if anything changes.