how to use groovy methods in soapUI

hi
I am learning soapui and trying to figure out how to use groovy scripts to make the test cases more dynamic. I have search through quite a bit of the forum and Internet resources to find out how to get around groovy in soapui but didn't quite find what I was looking for. Some of the questions similar to mine are left unanswered.... And I apologise if I repeat the topic (wasn't intentional)

anyway what I want to achieve is:
One of the test cases needs to generate lots of subscribers. These subscribers are email addresses. I wrote simple groovy script and using loop I can generate as many as I like. This is ok but now I am trying to incorporate this into test suite and I am a bit lost. Could someone point me to good examples or just briefly point out all the steps I need to do to utilize the function of generating subscribers?

Also, can I create common scripts library in the open source version? I am using the Pro version as well, but spotted groovy scripts can be added as a step in the free version.

Thanks for your time
anewbie