Ave - Blog Sidebar

You can use custom sidebars for blog posts and blog categories (blog archive) pages. 

Add Sidebars

Go to Liquid > Theme Options > Sidebar to enable sidebars globally. 

You can also find this option in the "Page Options". If you use "Page Options" sidebar will be enabled only for this page.

Edit Sidebars

Go to Appearance > Widgets and find the related sidebar. Now you can drag and drop any pre-built widget to create your own sidebar.