The Pseudo state is typically used to connect multiple transitions into more complex state transition's paths. For example, by combining a transition entering a fork pseudo state with a set of transitions exiting the fork pseudo state, we get a compound transition that leads to a set of orthogonal target states.
You can specify pseudo state properties in the pseudo state Specification window. In the same window, you can find the description of each property. Descriptions are presented in the description area of the Specification window.