When the CloudFormation template is deployed with SiteToSiteVpn=true, an SMA access policy is automatically created to grant the tunnel user access to the remote network CIDR (SiteToSiteRemoteCidr). No additional configuration is required for basic VPN access.
To allow access to other internal resources or enforce more restrictive controls, modify the access policies in AMC. See the SMA 1000 Administration Guide for access policy configuration details.