i do not undestand this step of prosecution
You have a right to be advised of the charges against you. That is what an arraignment is. Its the hearing where you are "arraigned" or advised of what you are charged with. You second question has to do with waiving formal reading of the charges.
Basically, you have a right to hear the legal and technical language of the charges against you.
Most attorneys will waive formal reading of the charges, and basically this means you don't want the judge to go step by step in legal terms on what your charges are.
Very Rarely do judges formally arraign an individual, usually if they are unrepresented.
An arraignment is the first court appearance in any criminal case.