Create terraform.tfvars file & add the below code in it.

cidr_block = "20.0.0.0/16"

cidr_block_subnet = "20.0.1.0/24"

name = "dev"

ami_id = "ami-0a606d8395a538502"

instance_type = "t2.micro"

region = "us-east-2"

tenancy = "default"

Note:- You need to change the ami_id value as it will be different for your environment. You can change value of rest of the variables as per your requirement or else you can leave it as it is.