Hi there,
Please add following code in Customize -> Custom -> CSS :
body.x-navbar-fixed-top-active .x-navbar-wrap {
height: auto;
}
Please select one of ‘Content Layout’ with sidebar under Customize -> Layout and design.
If you want to display default sidebar add some widgets in ‘Mainsidebar’ widget area. If you want to add specific sidebar, please check this link : https://community.theme.co/kb/unlimited-sidebars
Hope it helps.