I have below assignment

"A class of 8 students are giving presentations. The teacher needs to put them in order. Arun does not want to go first or last. In how many different ways could the order be arranged to keep Arun happy?"

And I know the answer is as below but I still don't understand its logic & concept, can you pls kindly help to explain again?

Answer:

There are 6 positions that Arun can be assigned,

namely positions 2,3,4,5,6,7;

Once that selection is made, there are only 5 positions left, besides the first

THere are 7 students that can fill the 1st position

There are 6 students to fill the one of the 5 positions left.

There are 5 students to fill one of the 4 positions left

There are 4 students to fill one of the 3 positions left

There are 3 students to fill one of the 2 positions left

There are 2 students to fill the last of position

The remaining student will be last (position 8)

6*7*6*5*4*3*2 = 30240