Okay, so there is no mistake.
1) Download the widgets plugin
2) unzip and DOUBLE CHECK that there's no duplicating yellow files - sometimes this happens. If this is the case, the plugin cannot be read correctly.
3) Upload the Widgets folder containing the PLUGIN to your plugins folder ie: wp-content/plugins/widgets
4) activate the plugin. If necessary, hit ctrl+F5 for hard refresh. You should see a new tab within the Presentation admin area. "Sidebar Widgets".
5) Upload Default sidebar to the Default Theme Folder. Your FTP program SHOULD ask you if you want to overwrite your current sidebar. Click yes - only if you haven't modified the sidebar.
6) Upload Classic sidebar to the Classic Theme folder. Your FTP program should ask you if you want to overwrite your sidebar. Click yes if you haven't modified the sidebar.
7) Upload functions.php to your CURRENT THEME folder
ie: wp-content/themes/default OR
8) Go to Presentation/Themes/Sidebar Widgets and start playing.
From the instructions above, the widget will NOT work if you are using your own theme. Uploading both Default and Classic sidebar.php respectively will only introduce widgets to those themes. It will NOT introduce widgets to your current theme, unless your current theme is indeed Classic or Default.
1) upload the plugin as mentioned above - double check that there's no duplicating folder.
2) activate the plugin
3) if necessary hit hard refresh
4) Go to Presentation/themes. You should see a new admin page offering Sidebar Widgets
5) go to Presentation/theme editor
6) Select YOUR CURRENT THEME (Not default or Classic, in this case)
6) Insert this code into the sidebar where you want the widgets to work - NOT APPEAR. Notice the difference in wording?
<?php if ( function_exists('dynamic_sidebar') && dynamic_sidebar() ) : else : ?>
<?php endif; ?>
7) save the sidebar file
8) Go to Presentation/Themes/Sidebar Widgets and start playing. What you drop and drag here, will APPEAR in your sidebar, once you save your playing.
Hope that clears up any confusion