First and foremost you need select your how many widgets you want for your website from Appearance – Theme Options – Main Settings – Footer Widget Layout.
Then you need to create menus by going to Appearance – Menu.
Create menus and assign what pages you want to each menu you have create.
Then if you want to assign menu to the widget, you will need to go to Appearance – Widget and select Custom Menu and drag it into any of the widget of your choice. Give it a title if you want and then select your menu.
For plugins that you want to be on the widget, you need to click on them on the widget and select on which of the widget you want it in.
For embedding code, use the Text Box.
You can modify positions by dragging and dropping between widget columns or within a widget column.
NOTE: They are called Footer Column 1, Footer Column 2, Footer Column 3
Hope this helps.