Permissions how to get read and write access to system files

I am trying to Move the extracted Adwaita Dark folder to the ‘usr/share/themes’ folder when I get the message' Error moving file: Permission denied'

Put sudo before the command for move the folder.

If you run:

gksudo nautilus /home/$USER

You can copy the data. The folder you are copying to is owned by root so your user has no access, use the command will get you the access you need

Thanks, I have ran this and get the following:

andy@andy-Inspiron-910:~$ gksudo nautilus /home/$USER
Initializing nautilus-gdu extension
** (nautilus:2308): DEBUG: Syncdaemon not running, waiting for it to start in NameOwnerChanged
Shutting down nautilus-gdu extension
andy@andy-Inspiron-910:~$

Still unable to copy to root.

Nautilus also pops up after the command, but I'm not sure what I should be doing next.

I am just copy & pasting the folder within Nautilus is this correct ?

Copy the files you need to the place you want

Thanks sorted :)