okay ...
you are more than welcome first ...
okay .. download the plugin from the site you have found it one .. maybe like wp-plugins.net .. or some other site that has the plugin you want to use ..
most likely this will be in a .ZIP format ..
unzip to your compuer .. i suggest your desktop since this is the easiest place to find it ...
login to your site via FTP ... usually through a FTP client like SMARTFTP or CUTEFTP ... this will list the "guts" to your site ...
if your wordpress is at yourdomain.com then you should see a folder named wp-content .. otherwise you will need to loate the wordpress folder ..
once under wp-content .. you should see "plugins" ...
from there ... upload the folder on your desktop that you unzipped to the plugins folder on your site ...
** most plugins come with instructions - FOLLOW THEM as I am unaware of the plugin you are wanting to install **
login to the wordpress via the login.php ... and then go under Plugins and "ACTIVATE"
i think i have covered it pretty good .. sorry if i mispelled something or oerlooked a step ..
i will help you through it ..
DP