Amendments are changes or modifications to the constitution. Amendments are to be proposed and ratified before put into application.
Our constitution has 27 amendments. This means that 27 changes and modifications have been made to keep up with the changing times.
Amendments don't have to be proposed by just one branch of government. Congress or a state may propose a possible amendment.
3/4ths of the Congress must vote in favor of an amendment. It is the same for the states in that 3/4ths of the states must vote in favor of an amendment.
No state, without its consent, will be deprived of its place in the senate. This means that all states are represented in the senate unless the state says otherwise.