The viewport defines the "window" into your application. This article discusses where this comes into play.
This article discusses how Eyes compares a test to a baseline where each of these is compromized of a sequence of checkpoints that may have changed over time.
This article explains the notion of the batch and provides an index to other topics that show to use batches in the SDK and the Test manager.
The match level provides a way for a user to control how similar the checkpoint baseline images need to be, in order to be considered "matched". This article desscribes the various match levels and how to apply them to all checkpoints or to a specific checkpoint or region in a checkpoint.
This article describes how to do cross environment testing, which allows you to test your application on multiple platforms using a single, common baseline.