these are a lot of questions.. I would recommend you to have a look at our video tutorial here: http://rapid-i.com/content/view/189/212/lang,en/
Furthermore you can have a look at the RapidMiner user manual which can be found here: http://rapid-i.com/content/view/36/210/lang,en/
Last you can have a look at the example processes found under Samples/processes in your RapidMiner Repositories View.
I think this should answer most of your questions.