expand docs

Author: sblack4

README.md

@@ -12,6 +12,7 @@ Creates an S3 bucket suitable for receiving VPC flow logs from one or more AWS a
 Example:
 
 
+Create the bucket with this module.
 ```
 module "vpcflowlog-bucket" {
   source              = "rhythmictech/aws-vpcflowlogs/terraform"
@@ -21,6 +22,20 @@ module "vpcflowlog-bucket" {
 }
 ```
 
+Then create the flow logs in each of the allowed accounts. Logs will flow back to the bucket in the original account.
+```
+module "vpcflowlogs" {
+  source = "git::https://github.com/rhythmictech/terraform-aws-vpcflowlogs.git"
+
+  create_bucket      = false
+  create_kms_key     = false
+  region             = var.region
+  vpc_ids            = [module.vpc.vpc_id]
+  vpcflowlog_bucket  = module.vpcflowlog-bucket.s3_bucket_name
+  vpcflowlog_kms_key = module.vpcflowlog-bucket.kms_key_id
+}
+```
+
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements