The layout of the Sidebar for any given Entity is based on the order and configuration of its Properties. You can modify the order using the Entity Type Editor, and you can change each Property by using the Data Tables and pressing RightClick on a Column Head.
Some Properties come standard with every Entity. These have fixed positions on the Sidebar and can't be moved. These are:
Name - Always in the heading.
Thumbnail - Always in the heading.
Image - Legacy. Always at the top of the body.
Icon - Not visible in sidebar. Only used in tags and map markers.
Spoiler - Work in progress. Not visible in sidebar. People with spoilers hidden will not see the sidebar.
You can rename a Property's name to be more human friendly. Unlike IDs, Property names don't have to be unique.
You can hide Properties from the Sidebar by marking them as Hidden. This is useful for Properties that are used for aiding editors such as datamined identifiers.
By default, Relationship Properties will be shown as:
A single row if there's one relationship.
Multiple Entity Rows if there's more than one relationship.
Hidden if there are no relationships.
To ensure the Sidebar always renders Entity Rows for a Property, even if there's only one, mark it as a List.
By default, Relationships in a List are ordered by the target Entity's name Property. You can change this to any other Property, in either ascending or descending order.