Hello Kasina,
First, my congratulation that you have created virtual services successfully from RR pairs and by Recording using the DevTest Portal.This is what we intended SV Test Drive users to achieve.
SV Test Drive is targeted to new users and provides guidance to understand the basics of Service Virtualization. It grants access to the product's web UI, the DevTest Portal. In this Web UI you can create projects (see guided tour 'Practice - Portal Introduction'). However, features of it's sibling product 'Application Test', such as creating test cases from scratch, adding assertions, filters and others are not supported by DevTest Portal, but by DevTest's fat client called 'Workstation', which is not part of the SV Test Drive trial, unfortunately. Using the Portal, you can create Baseline tests from virtual services automatically (see tour 'Assist - Validate VS by Baseline Test'), and execute them (see 'Assist - Run Baseline Test'). Those baseline tests will have assertions that are created automatically.
If you want to take the next step and to leverage DevTest Workstation, I recommend contacting the CA customer team using the 'Garage' button on the SV Test Drives's landing page. This team will discuss the best options for you to proceed. Among those options are using a full SV installation in AWS (SV on Amazon AWS) or Microsoft Azure (SV on Microsoft Azure), for which you need to bring your own license (BYOL), which could be a temporary one.
To learn about test cases and how to create them using DevTest Workstation, I recommend following the CA Application Test Tutorials.
Hope that helps.