Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
As pertaining to the playing of a single reed woodwindinstrument (such as a saxophone or clarinet), a setup is the choice in reeds and mouthpieces a person has made. Players will often have several setups of a selection of these reeds and mouthpieces: one for jazz playing, one for legit playing, etc.