Custom Logo :
The theme displays site title and tagline by default, as shown on the demo. You can also display a custom logo, and optionally hide the site title and tagline.
Main Menu :
To set up menu in your theme please go to Appearance > Menus.
Here You can get list of Pages, Posts, Custom Links, Categories you can choose your menus by select that page and click add to menu.
After adding menu you can change the menu name in Menu Structure > Menu Name also save your menu by clicking Save Menu button.
All themes displays menu by default if you select Display Location > Main Navigation checkbox. Also click Save Menu once again.