This repo goes ever creating a simple EC2 instance using Terraform.
terraform init => Initializes a working directory
terraform plan => Gives a dry run of what will happen when you create your resources.
terraform apply => Creates the specified resource
terraform destroy => Destroys the created resource
Once a resource is created, a file terraform.tfstate is created. Terraform needs a way to know what resources are created. This is tracked using the terraform.tfstate file.