how to implement wp_is_mobile on themes?

wp_is_mobile() this function is for code the device on which you viewing site is mobile. i mean this condition will true if you view site in mobile. now as per your question you want to display slider and sidebar only in desktop then your code will be like below:

1. for sidebar

if (!wp_is_mobile() ) {
    get_sidebar();
}

2. for slider    
     if (!wp_is_mobile() ) {
            // slider related stuffs.
}