How to acquire keystore and truststore files to enable SSL?

I am assuming you asking about enabling SSL for ThingWorx at transport level so you can access it using HTTPS protocol. There many ways to get certificate:

1. Self generate as explained in the guide in step "Create self-signed certificate"

2. From commercial certificate authorities like Godaddy, Digicerts and many others - see https://en.wikipedia.org/wiki/Certificate_authority.