Logo
The option to change the logo is available in the Theme Options;
WP Admin/Appearance/Theme Options/Site logo
In the above page, you can change the logo for the header, favicon and logo that suits lighter background.
1. Recommended logo size is 185px X 35px, PNG format, transparent background, suitable to light background.
2. Recommended favicon size is 24px X 24px, PNG format.
3. Recommended logo size is 185px X 35px, PNG format, transparent background, suitable to dark background.
Main Menu
Configure menu from WP Menu option
Go to Appearance/Menus/Main Menu
Like any other standard WordPress website, use right-side content to list the pages, stores, categories, brands etc.
Use drag and drop to change the sequence and hierarchy in the menu.
Enter CSS Classes as "mega-menu" to convert child menu to mega menu appearance;
Add option in the sidebar to add in menu;
Footer
First set the background in footer from
Appearance/Theme options/Color style
Size: 1940px X 446px
As for the footer layout
First 3 column can be best managed by creating a menu and then listing that menu in footer widget.
Create a a new menu from Appearance/Menu
Select the menu in Appearance/Menu
for 4th column, Add Coupon Social Widget
This how you can configure the header, menu bar, mega menu, footer, social follow in footer.