How to generate Searchguard certificates with digicert

For testing purposes, Searchguard has been configured on the development environment and that works well. We need to configure the same setup on live environment but not with the demo certificates, instead, we plan to generate the keystore on digicert CA.
Can anyone please let us know the steps to generate the following from digicert.
1) kirk.jks
2) keystore.jks
3) truststore.jks
Or, is it possible to generate the same with java keytool(is that compliant)?

Our enviroment follows,
Elasticsearch - 5.3.0
Searchguard - 5.3.0
Windows server 2012