add some documentation in README

README.md

@@ -1,3 +1,17 @@
 # letsencrypt-haproxy
 
-A short script to auto renew all your certificate, and concatenate fullchain and privkey so haproxy is able to use it
+Some scripts to create and renew all your certificates, and concatenate fullchain and privkey so haproxy is able to use it
+
+## How to create certificate
+Create a certificate with let's encrypt, then concatenate fullchain.pem and privkey.pem, then store the certificate in haproxy given path.
+
+Usage :  
+./create-certificate domain.tld >> /var/log/create-certificate.log
+
+## How to renew certificates
+**Renew all certificate known by let's encrypt !**
+
+Usage :  
+./renew-certificate >> /var/log/renew-certificates.log
+
+