Improve the documentation on deploying custom resources

Author: mnapoli

Diff for: docs/guides/resources.md

@@ -1,12 +1,10 @@
 # AWS Infrastructure Resources
 
-If you are using AWS as a provider for your Service, all [_Resources_](./intro.md#resources) are other AWS infrastructure resources which the AWS Lambda functions in your [_Service_](./intro.md#services) depend on, like AWS DynamoDB or AWS S3.
-
-Using the Serverless Framework, you can define the infrastructure resources you need in `serverless.yml`, and easily deploy them.
+Serverless Framework deploys using the AWS CloudFormation engine under the hood. If you want to deploy AWS resources that are not natively supported by `serverless.yml` (like AWS DynamoDB or AWS S3), you can deploy anything via the `resources` section.
 
 ## Configuration
 
-Every stage you deploy to with `serverless.yml` using the `aws` provider is a single AWS CloudFormation stack. This is where your AWS Lambda functions and their event configurations are defined and it's how they are deployed. When you add `resources` those resources are added into your CloudFormation stack upon `serverless deploy`.
+Every stage you deploy with `serverless.yml` is a single AWS CloudFormation stack. This is where your AWS Lambda functions and their event configurations are defined and it's how they are deployed. When you add `resources` to `serverless.yml`, those resources are added into your CloudFormation stack upon `serverless deploy`.
 
 Define your AWS resources in a property titled `resources`. What goes in this property is raw CloudFormation template syntax, in YAML, like this:
 
@@ -34,7 +32,7 @@ resources: # CloudFormation template syntax
           WriteCapacityUnits: 1
 ```
 
-You can attach any kind of resource to your CloudFormation stack. You can add `Resources`, `Outputs`. You can also use [Serverless Variables](./variables.md) for sensitive data or reusable configuration in your resources templates.
+You can attach any kind of resource to your CloudFormation stack. You can add `Resources`, `Outputs`. You can also use [variables](./variables.md) for sensitive data or reusable configuration in your resources templates.
 
 Note: By supplying your resources at `resources.Resources` you may accidentally override resources as generated by the framework. To intentionally extend such resources, please use `resources.extensions`, see [Override AWS CloudFormation Resource](#override-aws-cloudformation-resource) section for more info.