docs: clarify benchmark

Author: iru

modules/services/cloud-bench/README.md

@@ -2,8 +2,9 @@
 
 Deploys
 
-- the required IAM Role and IAM Policies to allow Sysdig to run AWS Benchmarks on your behalf
-- An `aws_foundations_bench-1.3.0` benchmak task schedule on  `0 6 * * *`
+- The required IAM Role and IAM Policies (`arn:aws:iam::aws:policy/SecurityAudit`)  to allow Sysdig to run AWS Benchmarks on your behalf.
+- The required provisioning on Sysdig Backend to use this ExternalId-based, AssumeRole permissions.
+- An `aws_foundations_bench-1.3.0` benchmak task schedule on a random hour of the day `rand rand * * *`