Updating to make saving the catalog to disk optional

Author: bergerhoffer

modules/oc-mirror-oci-format.adoc

@@ -4,7 +4,7 @@
 
 :_content-type: PROCEDURE
 [id="oc-mirror-oci-format_{context}"]
-= Mirroring Operator images in OCI format
+= Mirroring file-based catalog Operator images in OCI format
 
 You can use the oc-mirror plug-in to mirror Operators in the Open Container Initiative (OCI) image format, instead of Docker v2 format. You can copy Operator images to a file-based catalog on disk in OCI format. Then you can copy local OCI images to your target mirror registry.
 
@@ -19,7 +19,9 @@ include::snippets/technology-preview.adoc[]
 
 .Procedure
 
-. Create the image set configuration file to retrieve the catalogs and images that you require.
+. Optional: Retrieve the catalogs and images that you require and save them to disk. If you already have the catalog image in OCI format on disk, you can skip this step.
+
+.. Create the image set configuration file:
 +
 .Example image set configuration file for copying to disk
 [source,yaml]
@@ -40,7 +42,7 @@ When using the OCI feature, only the `mirror.operators.catalog` setting is avail
 The `storageConfig` setting is ignored in favor of the location passed in to the `oc mirror` command.
 ====
 
-. Run the `oc mirror` command to mirror the images from the specified image set configuration to disk:
+.. Run the `oc mirror` command to mirror the images from the specified image set configuration to disk:
 +
 [source,terminal]
 ----
@@ -75,7 +77,7 @@ You can optionally use the `--oci-registries-config` flag to specify the path to
 Set the `location` field in the `registry.mirror` section to an alternative registry location that you want to pull images from. The `location` field in the `registry` section must be the same registry location as the one you specify in the image set configuration file.
 ====
 
-. List your directory contents and verify that the following directories were created:
+.. List your directory contents and verify that the following directories were created:
 +
 [source,terminal]
 ----