diff --git a/docs/wildcard.md b/docs/wildcard.md
new file mode 100644
index 0000000..d0955dc
--- /dev/null
+++ b/docs/wildcard.md
@@ -0,0 +1,46 @@
+# Install of existing wildcard certificate
+
+First of all, stop the suite using:
+
+`/opt/src/DD# ./dd-ctl down`
+
+To make certificate compatible with DD, you need to merge the fullchain with the private key of the certificate, the best way of doing this is concatenating two files in a new one:
+
+`/tmp/certificatw# cat fullchain.pem cert.key > /opt/DD/src/haproxy/certs/chain.pem`
+
+The fullchain.pem file must contain all the certificate chain, cert.key is the private key, it needs to end up something like this:
+
+```
+> cat /opt/DD/src/haproxy/certs/chain.pem
+-----BEGIN CERTIFICATE-----
+YDC ...
+...
+... PnQP
+-----END CERTIFICATE-----
+
+-----BEGIN CERTIFICATE-----
+5dSf ...
+...
+... Hwgs
+-----END CERTIFICATE-----
+
+-----BEGIN CERTIFICATE-----
+sI3q ...
+...
+... vZas
+-----END CERTIFICATE-----
+
+-----BEGIN RSA PRIVATE KEY-----
+vzKJ ...
+...
+... 2dLs
+-----END RSA PRIVATE KEY-----
+```
+
+Review the route where you created the new file chain.pem, it must be in /opt/DD/src/haproxy/certs
+
+Once this is done restart the suite:
+
+`/opt/src/DD# ./dd-ctl up`
+
+Domain certificate must work then.
\ No newline at end of file