Clover Transformation Designer
This is where you will spend almost all of your time when working with Clover. All Clover Editions (Designer, Designer Pro, and Designer Evaluation) use the same fundamental designer for putting together your data transformations.
When evaluating the meat of the product, this is the stuff you should become familiar with. The server components should be looked at once you have understood the concepts embodied in the Designer.
The Designer is an Eclipse plugin. If you are not interested in what this means, then you can completely ignore it as it is a Desktop application like any other. If you are a Java person, then it does not need any further explanation.
If you want to find out more about the Clover Editions, please go here.