If you are refering to deligates to a political party convention, seating the delegates means that the prospective delegate presents some form of identification, ususally a drivers liscense, to a volunteer at a table in a convention center somewhere The volunteer will find the delegates name on a list and the delegate will sign for his/her credentials. By signing the delegate is certifying that he/she is the person elected as a delegate according to the party rules and state or federal election laws. The credentials are usually large tags on a lanyard worn around the neck. It shows the delegates name, precinct, district or state depending on the convention and whether the person is a delegate or an alternate. With these "credentials" the delegates and alternates are allowed onto the convention floor. The alternates are not permitted to sit with the delegates. Everybody else has to sit in the bleechers. Remember that list the delegates signed? It is now given to the delegate committee. The committee reviews the list and if believes that there are no irregularities it will certify the list and pass it on to the Chair. "The delegates are seated." The chair calls the meeting to order, counts the number of delegates to make sure that there is a quorum-if there is then we all just sit back and wait for the speeches(to be over). This is just an overview based on what I've seen as a deligate. I hope it answers your question.