Hey im tryin to figure out how to cast out the fishing pole to even catch a fish.

You have to first equip the pole where your weapon is. Then you right click on the fishing icon in your spellbook (you should drag this icon out to your screen to make it easier). Then just right click on the bobber after it bobs.

I've just got a lure for my rod but how do you conect it to the fishing pole?

forget my last comment I've worked it out.

I'll answer for those who haven't worked it out. Right click on the lure in your pack and then click on the pole. You should have an icon next to the mini map displaying the time that the lure's buff has left.