No more space on drive.

Thanks for all the help received so far, steep learning curve but getting there.
2.1.7 loaded plug ins FTP to tmp, cams ok line working until I tried to update TSmedia, crashed, Green panel then on reboot no sat channels (network connection tested and fine) and message saying no more space probably why TSmedia and Kodi are "empty" Have 500gb hard disc and 16gb usb at the back. I have an external 1Tb Hd . where are plug ins/addons stored by default, how do I delegate the storage to the seagate external also what do you recommend putting what where? Should I uninstall plugins and move them? how to do this if necessary?
Afraid to change things at the moment , Should I reinstall lines to tmp?