Click start, right click on computer and click Manage. Under Storage, click on disk management. Find your drive. If you can find it, assign it a drive letter. You can format it here as well if it needs it. Make sure this is not your currently running hard drive with the os on it, but your new 3tb drive.
Your new drive needs to be initialized in disk management , partitioned , formatted and assigned a drive letter. If you want to use the drive as a single large drive you can but if you want to make a couple of 1 tb drives you can do that also and it can be done in disk management by making a number of partitions that you want and each one would be assigned a drive letter and treated just like seperate drives. But that's up to you and what you want to do with the drive.