KaySue,
Plugins are written by lots of different people, and they are all unique. Where you configure them also depends on the plugin. Many plugins, after you activate them, will place a new menu under the top Options menu. So after activating the plugin, click the Options tab, and look for a sub tab for that plugin.
You do need to activate the plugins. Just uploading them is not enough. From the Plugins menu, you will see a list of all *installed* plugins… just because they are installed doesn’t mean they are activated. You must click the “Activate” link in the far right column. On the plugins menu, you see the rows of installed plugins. If the row is grey or white colored, the plugin is *not* activated. If it is green, it is activated.