Conditional Statements behave as usual: if their Condition does not throw any unhandled Check Fail events then their Then Container is executed, otherwise their Else Container is executed instantly after the Check Fail event is encountered - so the remaining parts of the Conditions are skipped.
You can set a Conditional Statement to be Negated in the Properties View of its top node (called "If" by default). A Negated Conditional Statement executes its Then Container when its Condition fails and its Else Container when it does not.