This is the orchestration which shows how many of which instruments are needed to perform the piece. The number in parentheses after the title is the duration of the work. For example, the Bizet is 18 minutes long if played at the composer’s indicated tempo, and the movements are 5 minutes, 4 minutes, 4 minutes and 5 minutes in order.
The numbers underneath are the instrumentation. Winds are first. For the Mussorgsky, you have 3 flutes, 3 oboes, 3 clarinets and 3 bassoons.
Next are the brass: 4 (french) horns, 2 trumpets + 2 auxiliary, 3 trombones and 1 tuba.
You have the standard timpani plus 4 extra instruments (check the score to see what those are; could be triangle, gong, bass drum, etc.).
You have harp and the usual strings (violin, viola, cello and bass). At the end it has “percussion to be determined.”