Fix approval segregation of duties documentation

doc/user/project/merge_requests/approvals/rules.md

@@ -173,6 +173,7 @@ Some users (like managers) may not need permission to push or merge code, but st
 oversight on proposed work. To enable approval permissions for these users without
 granting them push access:
 
+1. [Create a protected branch](../../protected_branches.md)
 1. [Create a new group](../../../group/index.md#create-a-group).
 1. [Add the user to the group](../../../group/index.md#add-users-to-a-group),
    and select the Reporter role for the user.
@@ -180,7 +181,7 @@ granting them push access:
    based on the Reporter role.
 1. Go to your project and select **Settings > General**.
 1. Expand **Merge request (MR) approvals**.
-1. Select **Add approval rule** or **Update approval rule**.
+1. Select **Add approval rule** or **Update approval rule** and target the protected branch.
 1. [Add the group](../../../group/index.md#create-a-group) to the permission list.
 
    ![Update approval rule](img/update_approval_rule_v13_10.png)