When adding a new drive by default Ubuntu (like Windows) does not do anything to make the drive visible on screen or immediately usable. The drive needs to be partitioned, formatted and mounted before it can be written to. Partitioning and formatting is a simple matter of using GParted Partition Editor. Mounting is where things become interesting because without taking a few essential steps you'll typically find you cannot write to the drive you've just partitioned, formatted and mounted. The trick is to ensure that your user account has read/write permission for the drive in question. I do this by assigning ownership of the mountpoint to my user account. Here's how it's done:
Create a mountpoint for the drive and assign ownership:
cd /media && sudo mkdir name_of_your_mountpoint_as_you_see_fit && sudo chown yourusername:yourusername name_of_your_mountpoint_as_you_see_fit
Thereafter whenever you mount the drive to /media/name_of_your_mountpoint_as_you_see_fit you'll automagically have r/w permission to the root of that drive and all child folders whether mounted manually or automatically.