README.md in google-shopping-merchant-accounts-0.a vs README.md in google-shopping-merchant-accounts-0.1.0

@@ -1,8 +1,104 @@
-# Placeholder for Ruby gem google-shopping-merchant-accounts
+# Ruby Client for the Merchant API
 
-This is a placeholder for the future Google-authored gem google-shopping-merchant-accounts.
-This placeholder is being released on 2024-06-04 in order to reserve the name.
-The final gem should be available shortly after that date. If it has not been
-released in a timely manner, or if this placeholder interferes with your work,
-you can contact the Google Ruby team by opening an issue in the GitHub
-repository https://github.com/googleapis/google-cloud-ruby.
+Programmatically manage your Merchant Center accounts.
+
+Programmatically manage your Merchant Center accounts.
+
+Actual client classes for the various versions of this API are defined in
+_versioned_ client gems, with names of the form `google-shopping-merchant-accounts-v*`.
+The gem `google-shopping-merchant-accounts` is the main client library that brings the
+verisoned gems in as dependencies, and provides high-level methods for
+constructing clients. More information on versioned clients can be found below
+in the section titled *Which client should I use?*.
+
+View the [Client Library Documentation](https://rubydoc.info/gems/google-shopping-merchant-accounts)
+for this library, google-shopping-merchant-accounts, to see the convenience methods for
+constructing client objects. Reference documentation for the client objects
+themselves can be found in the client library documentation for the versioned
+client gems:
+[google-shopping-merchant-accounts-v1beta](https://rubydoc.info/gems/google-shopping-merchant-accounts-v1beta).
+
+See also the [Product Documentation](https://developers.google.com/merchant/api)
+for more usage information.
+
+## Quick Start
+
+```
+$ gem install google-shopping-merchant-accounts
+```
+
+In order to use this library, you first need to go through the following steps:
+
+1. [Select or create a Cloud Platform project.](https://console.cloud.google.com/project)
+1. [Enable billing for your project.](https://cloud.google.com/billing/docs/how-to/modify-project#enable_billing_for_a_project)
+1. [Enable the API.](https://console.cloud.google.com/apis/library/merchantapi.googleapis.com)
+1. {file:AUTHENTICATION.md Set up authentication.}
+
+## Supported Ruby Versions
+
+This library is supported on Ruby 2.7+.
+
+Google provides official support for Ruby versions that are actively supported
+by Ruby Core—that is, Ruby versions that are either in normal maintenance or
+in security maintenance, and not end of life. Older versions of Ruby _may_
+still work, but are unsupported and not recommended. See
+https://www.ruby-lang.org/en/downloads/branches/ for details about the Ruby
+support schedule.
+
+## Which client should I use?
+
+Most modern Ruby client libraries for Google APIs come in two flavors: the main
+client library with a name such as `google-shopping-merchant-accounts`,
+and lower-level _versioned_ client libraries with names such as
+`google-shopping-merchant-accounts-v1beta`.
+_In most cases, you should install the main client._
+
+### What's the difference between the main client and a versioned client?
+
+A _versioned client_ provides a basic set of data types and client classes for
+a _single version_ of a specific service. (That is, for a service with multiple
+versions, there might be a separate versioned client for each service version.)
+Most versioned clients are written and maintained by a code generator.
+
+The _main client_ is designed to provide you with the _recommended_ client
+interfaces for the service. There will be only one main client for any given
+service, even a service with multiple versions. The main client includes
+factory methods for constructing the client objects we recommend for most
+users. In some cases, those will be classes provided by an underlying versioned
+client; in other cases, they will be handwritten higher-level client objects
+with additional capabilities, convenience methods, or best practices built in.
+Generally, the main client will default to a recommended service version,
+although in some cases you can override this if you need to talk to a specific
+service version.
+
+### Why would I want to use the main client?
+
+We recommend that most users install the main client gem for a service. You can
+identify this gem as the one _without_ a version in its name, e.g.
+`google-shopping-merchant-accounts`.
+The main client is recommended because it will embody the best practices for
+accessing the service, and may also provide more convenient interfaces or
+tighter integration into frameworks and third-party libraries. In addition, the
+documentation and samples published by Google will generally demonstrate use of
+the main client.
+
+### Why would I want to use a versioned client?
+
+You can use a versioned client if you are content with a possibly lower-level
+class interface, you explicitly want to avoid features provided by the main
+client, or you want to access a specific service version not be covered by the
+main client. You can identify versioned client gems because the service version
+is part of the name, e.g. `google-shopping-merchant-accounts-v1beta`.
+
+### What about the google-apis-<name> clients?
+
+Client library gems with names that begin with `google-apis-` are based on an
+older code generation technology. They talk to a REST/JSON backend (whereas
+most modern clients talk to a [gRPC](https://grpc.io/) backend) and they may
+not offer the same performance, features, and ease of use provided by more
+modern clients.
+
+The `google-apis-` clients have wide coverage across Google services, so you
+might need to use one if there is no modern client available for the service.
+However, if a modern client is available, we generally recommend it over the
+older `google-apis-` clients.