Not able to figure out How to add new test cases of any existing project Please respond ASAP

Hi Support,

We are using Ready API! -Soap UI NG, I am automating the REST Web services using Discover REST API's.

Also we  are not able to figure out How to add new test cases of any existing project?

We are working paralley and we need to merge the testcases into single project ,could you let me know the procedure for this.

Thanks,

Rajendra Prasad