Here is the steps to assign menu on header and footer area:
Header Menu:
1. Create the new menu
add menu on the menu area. Here you can add post , pages. custom links and Categories. YOu can take reference of this site to know more on this WordPress Menu User Guide
2. Select Theme Locations from Menu Setting Section
3. Save the setting, now you will be able to see menu on header area
Footer Menu:
1. Create the new menu
add menu on the menu area. Here you can add post , pages. custom links and Categories. YOu can take reference of this site to know more on this WordPress Menu User Guide
2. Select Theme Locations from Menu Setting Section
3. Save the setting, now you will be able to see menu on header area