cant copy and paste folders as root

EDIT :

Hello, thanks for responses.

I'm trying to install a plugin for gimp - its this one : https://sourceforge.net/projects/exportselectedlayersgimpplugin/

This is downloaded onto my second hard drive in a generic folder and I'm trying to move or copy and paste it into a gimp plugins folder like I used to do on windows.

What I've tried.

In gimp i have gone to edit/prefferences/folders/plugins

and found these two lines

/home/karribu/snap/gimp/372/.config/GIMP/2.10/plug-ins & /usr/lib/gimp/2.0/plug-ins

The first one doesn't let me copy and paste even when opened as admin. The second link doesn't lead anywhere and I get an error from ubuntu when i try to open as admin "oops something went wrong, unable to find the file"

I hope this is more clear than my post last night, thanks.

running 20.04.3 LTS

many thanks

First, there may be no need for you to copy files as root in this case:

• First check whether your plugin is not already packed in the gimp-plugin-registry package. Use Software or the command sudo apt install gimp-plugin-registry to install it. Remove it supplying remove in the above command`.
• Alternatively, you can manually install plugins, but consider to do this as normal user. In Gimp, look up where plugins are stored in Edit - Preferences - Folders - Plugins. Among the folders, there will be one in your home directory as well (starting with /home/<yourlogin>/). Just copy plugins there: no root access needed.
• If you need to copy to system locations, for example because you want the plugins to be available to all users of the system, then learn how to work with the admin:// URI.

So thus we come to your main question. To copy as administrator, open nautilus with a command (either in the terminal, or in the "Run" dialog you see after hitting Alt+F2):

nautilus admin:///app/lib/gimp/2.0/plug-ins

This opens the folder with admin privileges (note this is my plugins folder, corresponding with a flatpak install, yours may and likely will be different). Open a second nautilus window, and copy the files from that second window to that first one.