FTP Client and Plugin Browser

Hi
I am trying to debug my website. All I have is ftp access to the user space where my site is. Questions:

1. I am using windows and would like to know what is the recommended FTP client to upload site components ie plugins etc? I am currently able to login via windows explorer but seems I am unable to upload directories properly. I just tried to upload most recent php-browser-detection folder and now I can see two of those, old and new. I thought it would overwrite old, since I am trying to upgrade this plugin

2. Related to my 1st question, what exactly is ‘Plugin Browser’? Basically in the install section of the above plugin it says:
-Automatically install through the Plugin Browser or…
-Upload entire php-browser-detection folder to the /wp-content/plugins/ directory.
-Activate the plugin through the ‘Plugins’ menu in WordPress.

3. Finally: What does this means:
“Activate the plugin through the ‘Plugins’ menu in WordPress”

If that means to login to my site via wordpress, it is not going to work since when I login to ‘dashboard’ it shows no content (hence this post, I am trying to debug the site)