Overview
I investigated how to link content of different content types to each other, and here are my notes.
Specifically, as shown below, item 1 is connected to a content item called image 1 through a field called iiif_image2.
The goal is to add a link to item 1 on the image 1 page.
I referenced the following article for this implementation.
Method
Adding a View
Navigate to /admin/structure/views and click “+ Add view”
Check the “Create a block” option.
Configuring the View
On the next page, configure the Advanced settings.
Relationship
Add a relationship for field_iiif_image2. This is important for associating the two content types.
You need to check “Require this relationship”. I understand this means that items without this field will not be displayed.
Contextual Filter
Next, add a contextual filter for the landing page of the current content type. This is how the actual node ID used in the view is obtained. This way, only pages that have the same node ID in field_iiif_image2 can be found.
Search by ID (Content)
Check “Provide default value” -> “Content ID from URL”
The result looks like the following.
In the “Update preview” section, enter the media node ID (here, 62602). Links to items that reference this media will be displayed.
Adding the Block
Access the following:
/admin/structure/block
For example, press the “Place block” button next to “Content”.
Place it at /node/*.
As a result, as shown at the beginning, you can display the item to which the image belongs.
Summary
I apologize that the terminology used is inconsistent and may be confusing, but I hope this serves as a helpful reference.