Install SSL certificate on my web server in AWS and write automatic update script

I have a web server running on a Linux virtual machine in Amazon AWS. The web server is Apache + PHP + Mysql stack. I need to install an SSL certificate on the web server so that the website support HTTPS. I also need someone to write an automatic update script so that it can automatically update the certificate when it is going to expire. I want to use following free SSL certificate service: [login to view URL] If you had experience using the letsencrypt with AWS, please bid.