Remove 'decedent' from README.

README.md

@@ -294,29 +294,39 @@ You can enable Extended Dismax search on this module's configuration page at
 `admin/config/islandora/advanced_search`. This will affect all Advanced Search
 and Search blocks provided by this module.
 
-
-
-## Configure Collection Search
+## Configure Search Fields for Collection Search
 
 See "Requirements" for a discussion of the use of `field_member_of`.
 
-To support collection based searches you need to index the `field_member_of` for
-every node as well define a new Search API field that captures the full
-hierarchy of `field_member_of` for each repository item.
+In this section we set up fields in our Solr index (using Search API) 
+that index a node's parent ("Member of") and all its parents' parents,
+recursively ("Descendant of"), the latter achieved by using Search API's 
+"Index hierarchy" processor.
 
-Add a new `Content` Search API field `field_decedent_of` to the index at
-`admin/config/search/search-api/index/[your default index]/fields`.
+First ensure that your hierarchy field (assumed for convenience to be `field_member_of`)
+is indexed at `admin/config/search/search-api/index/[your default index]/fields`. 
+We will assume that the Search API field's name is "Member of". The field type
+should be "Integer".
 
-![image](./docs/field_decedent_of.png)
+Next, create a second Search API field, based on the same Drupal field. We'll
+call this one "Descendant of". It is also an Integer.
 
-Then under `admin/config/search/search-api/index/[your default index]/processors`
-enable `Index hierarchy` and setup the new field to index the hierarchy.
 
-![image](./docs/enable_index_hierarchy.png)
+![Search fields Member of and Descendant of set up](./docs/field_descendant_of.png)
 
-![image](./docs/enable_index_hierarchy_processor.png)
+Then, under the Processors tab (`admin/config/search/search-api/index/[your default index]/processors`)
+enable the checkbox for `Index hierarchy` and at the bottom of the page, setup the processor
+to index hierarchy for "Descendant of" (but not "Member of").
+
+!["Index hierarchy" checkbox selected](./docs/enable_index_hierarchy.png)
+
+!["Decendant of" selected under Index Hierarchy processor settings.](./docs/enable_index_hierarchy_processor.png)
+
+
+This "Descendant of" field now contains a list of all its ancestors, so can
+be used as a contextual filter on views, thereby allowing the view to display all 
+descendants of a given node. 
 
-The field can now be used limit a search to all the decedents of a given object.
 See the section below, "Collection search", to finish configuring your site
 for collection and sub-collection search.
 
@@ -324,16 +334,16 @@ for collection and sub-collection search.
 
 ## Configure Views
 
-Create a Search API view that uses your index. 
-
-The configuration of views is outside of the scope of this document, please read
-the [Drupal Documentation](https://www.drupal.org/docs/8/core/modules/views), as
+Detailed instruction on the configuration of views is outside of the scope of this document.
+Please read the [Drupal Documentation](https://www.drupal.org/docs/8/core/modules/views), as
 well as the
 [Search API Documentation](https://www.drupal.org/docs/contributed-modules/search-api).
 
-However, do NOT add the "Fulltext search" filter, despite that it is the "usual" way of
-setting up a Search view. All fulltext searching (and fielded searching) will 
-be handled by blocks provided by this module.
+To use the Advanced Search module, you will need to create at least one view that
+is based on Search API and uses Solr. However, do NOT add the "Fulltext search"
+filter, despite that being the "usual" way of setting up a Search view. All 
+fulltext searching (and fielded searching) will be handled by blocks provided 
+by this module.
 
 ### Exposed Form
 
@@ -348,7 +358,7 @@ The Advanced Search Block requires that if present the Exposed forms
 `Input Required` will prevent any search from occurring unless the user puts an
 additional query in the Exposed form as well.
 
-![Form Style](./docs/basic-input.png)
+![Exposed Form set to Basic.](./docs/basic-exposed-form.png)
 
 ### Collection Search
 
@@ -357,24 +367,27 @@ This module's "Advanced Search" block can be set up on a
 that can contain other entities). This block allows the user
 to select whether they want the search to include sub-collections.
 
-![image](./docs/include_subcollections.png)
+!["Include Sub-collections" checkbox in the Advanced Search Block.](./docs/include_subcollections.png)
 
 The following instructions describe how to set up this feature.
 
-![image](./docs/view_advanced_setting.png)
+First, in your Search API view, set up **two** contextual filters:
 
-Here a relationship is setup with `Member Of` field and we have **two**
-contextual filters:
+1. "Member of" (Direct descendants only)
+2. "Descendant of" (All descendants)
 
-1. `field_member_of` (Direct decedents of the Entity)
-2. `field_decedent_of` (All decedents of the Entity)
 
-Both of these filters are configured the exact same way.
+![Views config showing two contextual filters.](./docs/view_advanced_setting.png)
 
-![image](./docs/contextual_filter_settings.png)
+Both of these filters are configured the exact same way. The only configuration
+to set is "When the filter value is NOT available" then "Provide default value". 
+Under Type, select "Content ID from URL".
 
-These filters are toggled by the Advanced Search block to allow the search to
-include all decedents or just direct decedents (*documented below*).
+![Contextual filter showing "Content ID from URL" selected.](./docs/contextual_filter_settings.png)
+
+These two contextual filters are used by the Advanced Search block to
+expose the toggle to search direct descendants or all descendants
+(documented under "Advanced Search Block", below).
 
 ### Paging
 
@@ -481,12 +494,13 @@ the models you want to display the search on, e.g:
 
 ### Advanced Search Block
 
-For any valid search field, you can drag / drop and reorder the fields to
+For any valid Search API field, you can drag / drop and reorder the fields to
 display in the advanced search form on. The configuration resides on the block
-so this can differ across views / displays if need be. Additionally if the View
-the block was derived from has multiple contextual filters you can choose which
-one corresponds to direct children, this will enable the recursive search
-checkbox.
+so this can differ across views / displays if need be. 
+
+If the view this block is attached to has *two* exposed filters, then you can 
+choose which one corresponds to direct descendants. This will enable the 
+"Include Sub-Collections" search checkbox on the Advanced Search block.
 
 ![image](./docs/advanced_search_block_settings.png)