Unable to move files to External Drive from MacBook, with "no entry sign" error.

I have a MacBook Air (Ventura) and have connected my external hard drive in order to move some folders over as backup. When I try to copy the folders from the Mac over to the external drive, it shows the no-entry sign.

• Using Get Info on the external hard drive, permissions show my name (Me) as having Read & Write access (I, however, do not)
• Unlocking the padlock and trying to change permissions for staff and everyone gives the message "The operation can’t be completed because you don’t have the necessary permission."
• The plus, minus and three-dot menu at the bottom of the window is greyed out.
• I've read about a toggle for "Ignore ownership", but I do not have that option in the Get Info window.

Any idea how I can access my hard drive?

[Re-Titled By Moderator]