The first day of trial often includeds meetings with the Judge to decide certain evidentiary issues, stipulations and procedures. It may also inlude jury selection if the case is tried before a jury and not a judge ( bench trial ). If the actual trial starts then the Judge or Clerk will swear in the jury and the Judge will give some instructions. Thereafter the attorneys will each make an opening argument to the Jury and then the Prosecution will start to call witnesses who can be cross examined by the defense attorney.
why are you not getting this very basis information from your attorney? You have very serious charges and if you do not have any attorney, you should immediately consult with and retain one.