Hi, I am Dave, I will help you with this.
Are you short of space on the C drive is that why you went to transfer files from the C drive to the D drive?
If that is what you are trying to do:
Open Windows File Explorer
In the right hand pane, right click your Documents folder and choose Properties
Select the Location tab
In the Location box, type D:\Documents then click Apply and OK.
Do not just specify the D drive, oyu must specify a folder name.
When that move completes, do the same for Pictures, Videos and Music
Each time, provide a new folder location, for example, Pictures will go to D:\Pictures