Deploying an instance on AWS via terraform

So I am trying to explore terraform and how to deploy instances on cloud using terraform.
first follow this to configure aws cli on your windows
http://www.cloudishes.com/2017/12/amazon-aws-automation.html
Not mandatory but recommended.
 Refer my previous post on installing terraform on windows.
Now

provider "aws" {
  access_key = "<access_key?"
  secret_key = "<secret_key?"
  region = "ap-south-1"
}
resource "aws_instance" "example" {
  ami           = "ami-cce794a3"
  instance_type = "t2.micro"
}

create a aws.tf file and paste this code.
Run

terraform init
terraform apply

from the same directory and it might ask you to type yes for a plan. Do that and you are done. Now you can go see your instance on AWS and it is live.
you will notice that it keeps asking for a build plan every time you do this. Instead you can create a build-plan first and then apply that.

terraform plan -out build-plan
terraform apply build-plan