Take the referance below code to build the VPC in your account .. use referance for CIDR calculater https://www.davidc.net/sites/default/subnets/subnets.html
module "vpc-dev" {
source = "git@github.com:sbrTechWorld/terraform-vpc-module.git"
product = "sales" environment = "dev" vpc_cidr = "10.0.0.0/23" tenancy = "default" public_subnets = "10.0.0.0/25,10.0.0.128/25" private_subnets = "10.0.1.0/25,10.0.1.128/25" availability_zones = "eu-west-2a,eu-west-2b"
}