How to read and use SoapUI API for non Dev people?

Hello,

i don't have any background in development especially in java.

I would like to learn how to read and use SoapUI API from SoapUI API docs (http://www.soapui.org/apidocs/index.html?overview-summary.html)

something like testRunner, context, messageExchange.

how do i know which method or which variable i can use for i.e context variable, testRunner variable

usually i see someone write like

context.expand

or something like

testRunner.testCase.testSuite

where i can get this information?

I would like to understand how people know they can user expand in the context variable etc

many thx