Let's Encrypt and IIS
My preferred client for Windows (mainly because it's just what I'm used to, and it's super simple) is win-acme. So the first step is to download that and extract it in a "scheduled tasks" folder on my desktop (personal preference for tasks).
I start (as admin)
letsencrypt.exeand press by default:
» N: Create new certificate
» 1: Single binding of an IIS site
» Choose site
SSL binding should be added as well as a scheduled task for renewal. I can start the exe file at any time to reconfigure HTTPS for any sites.