United States of Greater Austria was created by a several smaller local monarchist states that banded together under the strongest one (Austrian Empire) to survive an onslaught of French Empire
and Scandinavian Monarchy
during the Unification Wars. They succeeded, but overtime this temporary alliance grew stronger and stronger, soon after changing into one, decentralized state.
Today United States of Greater Austria remains an union of several autonomous areas varied in size and exact level of autonomy, all according to many various bilateral agreements signed between central government (formerly Austrian Empire government) and various member states and autonomous regions (formerly allies of Austrian Empire). Trying to describe the entirety of the member states in details would require a much longer and dedicated text, thus it will be omitted here.
Central government operates as an extension of the power of an Austrian emperor. Its power is limited to personal domain of an emperor - meaning the central Austrian Empire - while at least trying to oversee the rest, with its many autonomous regions self-governing themselves. This dualism is visible even in emperor's personal titulature - he is both king and emperor, the first one of Austria itself while the second of entirety of empire.
There is also an imperial parliament, known simply as Reichsrat. It is divided into two houses. Upper - called House of Lords (Herrenhaus) is composed of representatives of member-states and autonomous regions. Lower - House of Deputies (Abgeordnetenhaus) includes democratically elected representatives of entire population of United States of Greater Austria.
The exact number of said democratic representatives is 203 - as it once was in Austria-Hungary
. Each of the member-states and autonomous regions has a set number of representatives that depends on their population number.