two questions ~~
【That same morning, the loudspeaker at W. E. Greiner Junior High School, just across the Trinity River from the Texas School Book Depository, announced that students could go to tomorrow's motorcade provided their parents came for them. It was the opening period; Warren Harding's fourteen-year-old son was attending his first class of the day.】

what does"It was the opening period;"mean?does it indicating the opening of a new semester ,or the opening of motorcade ?

Question

two questions ~~
【That same morning, the loudspeaker at W. E. Greiner Junior High School, just across the Trinity River from the Texas School Book Depository, announced that students could go to tomorrow's motorcade provided their parents came for them. It was the opening period; Warren Harding's fourteen-year-old son was attending his first class of the day.】

what does"It was the opening period;"mean?does it indicating the opening of a new semester ,or the opening of motorcade ?

Answer

The opening period is the first period of the day. Lessons are called "periods".

Answer

iN SOME SCHOOLS STUDENTS GO TO WHAT IS CALLED THEIR "HOMEROOM" BEFORE THEY ACTUALLY BEGIN CLASSES FOR THE DAY.  IN THIS CLASS ATTENDANCE IS TAKEN, ANNOUNCEMENTS MADE,AND THE PLEDGE OF ALLEGIANCE IS RECITED.
tHAT IS PROBABLY WHAT THEY ARE REFERRING TO.