Update readme with instructions for placing blocks with other themes (#197)

* Update readme with instructions for placing blocks with other themes

* Add more detail to readme instructions

Author: tonypaulbarker

README.md

@@ -4,7 +4,29 @@ Provides paginated navigation through pages with an overview page and
 block. A part of the LocalGovDrupal distribution, that can also be installed
 stand-alone.
 
-Content types:
+## Install process:
+
+Standard Drupal module installation process applies. But...
+
+The 2 x block configuration files are only installed if you are using the LocalGov Drupal base theme or Scarfolk theme. 
+So before installing this module, copy these two files 
+
+config/optional/block.block.localgov_guides_contents_base.yml
+config/optional/block.block.localgov_guides_prev_next_block_base.yml
+
+and make the following changes to the copies of the files:
+
+- name the copies of the files consistently for your theme, e.g. localgov_guides_contents_mytheme.yml
+- update the id parameters, .e.g id: localgov_guides_contents_mytheme
+- replace "localgov_base" with your theme name, update the id  and set a region available to the theme:
+
+Note: if you have a long machine name for your theme, consider shortening the naming used here to avoid running into errors.
+
+You can revert these changes after module installation as these files are no longer needed.
+
+Alternatively, add these two blocks from the Drupal block layout admin page.
+
+## Content types:
 
  * Overview - the top level section for each guide;
  * Page - the page that can be placed in a guide.