Ok, go to the Plugins are of your Admin control panel.
When you see “Activate” and “Edit” click the edit button.
On the right, you will see the files it contains. Click the “README” file and follow the instructions.
For example, The SEO says to do this
“1. You can either use the automatic plugin installer or your FTP program to upload it to your wp-content/plugins directory
the top-level folder. Don’t just upload all the php files and put them in /wp-content/plugins/
.
1. Activate the plugin through the ‘Plugins’ menu in WordPress
1. Visit your SEO options (*Options – All in One SEO*) for WordPress 2.3.x, (*Settings – All in One SEO*) for WordPress 2.5.x-2.8.x
1. Configure any options as desired, and then enable the plugin
1. That’s it!”