its ok I fix it ! here the steps :
first I installed KeyStore Explorer
I creat a Store myhoststore.jks
I import the pair keys from myhost.ddns.net-chain.pem and myhost.ddns.net-key.pem And import the two certificate ca-myhost.ddns.net-crt.der and myhost.ddns.net-crt.der
in tomcat I edit the server.xml
Connector port="8443" protocol="HTTP/1.1"
maxThreads="150" SSLEnabled="true" scheme="https" secure="true"
clientAuth="false" sslProtocol="TLS"
keystoreFile="C:\Program Files\myhoststore.jks"
keystorePass="xxxxxxxxxxx" keyAlias="myhostletsecript"
and I have a nice red cadnat in the browser