To edit the Menu you need to search and edit the links directly in your template code.
To edit the slider you need to changes the images and urls directly in your template code.
About Delivery Lite
Delivery Lite is a free Blogger template adapted from WordPress with 3 columns, responsive design, seo friendly, left and right sidebars, ads ready, footer columns, slider, posts thumbnails, simple look and neutral colors.
Excellent template for blogs about any general topic or news.