Customize → Category
This is category page eg :Category Demo in here you can setting layout of this page
So when you in the Customize then you should click to Blogs Categories
Sidebar Layout
Right Sidebar.
You can read more for the widgets at here : Sidebar
Post Layout
You can setting layout posts for yourself
Title: Turn on or turn off Title
List Post.
Grid Post.
POST META: Turn on or turn off each post Meta