how to install a new plugin on server??

[nishantnigam]

hey guys i want yo know how can i install a new plugin on my existing joomla website when i try to install from administrator backend it says directory doesn`t exist
i guess i have to copy the zip file and then try to install
i need a step by step guide to install plugin or any extension on the server
thanks

[Per Yngve Berg]

Help->System Info

Check weather the temp directory is writeable (last line).

[nishantnigam]

no it is unwritable
the temp path and the log path in my directory permissions is unwritable
its is mentioning like var/www/localhost/example.com/html/tmpl

thanks for ur reply Per Yngve Berg
i may require more help

[nishantnigam]

guys i am waiting for help !!

[Per Yngve Berg]

Do the directory exist?

[nishantnigam]

yes the directory exists ..
i have made few changes in the tmp path instead of writing the whole address i have used only /tmp and it works..