I am trying to setup a VPN connection using AWS VPC. I have generated the VPN configuration files and have sent to the client. However the client is asking for the Blue highlighted info in the attached image. I'm wondering where can I get these info.
Your Third party VPN device should be the AWS Managed VPN, to get more information use the AWS CLI to interrogate the VPN Gateway see link https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_VPN.html
Also the question regarding the "redirect to" concerns the subnets on the VPC side, where after the VPC "Routing Table" you will have a "NAT Gateway" to translate the customer network into the private IP range used in the VPC.
See link on NAT gateways and VPC. https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-nat-gateway.html