Ultra has 2 widget areas: Sidebar and Footer. Add widgets to them in AppearanceWidgets. Ultra uses the classic Widgets screen by default, where you drag a widget into an area.
Sidebar
The Sidebar area sits to the right of the content. It shows on posts, the blog page, archives and search results. On pages it shows with the Default template, Default – No Title and the Page Settings layouts that keep the sidebar.
The sidebar appears only when the area has at least 1 widget. To remove it, delete all its widgets.
Footer
The Footer area sits above the bottom bar. Ultra gives each widget its own column. With 4 widgets, the footer has 4 columns. Ultra styles the columns for up to 10 widgets in one row. On small screens the widgets stack in one column.
To hide the footer widgets on one page, turn off Footer Widgets in the Page settings box.
Design
Ultra Premium sets the colors of both areas in Theme Design > Sidebar and Theme Design > Footer.