I will assume these are these six jokes about books that are to be delivered.

1. Little boy's joke about books.
2. Little girl's joke about books.
3. Teenage girl's joke about books
4. Teenage boy's joke about books.
5. Man's joke about books.
6. Woman's joke about books.

How many ways can the six jokes about books be delivered if a man's joke is told first?

We MUST choose the 1st joke only one way, the man's joke.
That's 1 way to choose the first joke.
We can choose the 2nd joke as any of the 5 remaining jokes.
That's 1*5 ways to choose the first two jokes.
We can choose the 3rd joke as any of the 4 remaining jokes.
That's 1*5*4 ways to choose the first three jokes.
We can choose the 4th joke as any of the 3 remaining jokes.
That's 1*5*4*3 ways to choose the first four jokes.
We can choose the 5th joke as either of the 2 remaining jokes.
That's 1*5*4*3*2 ways to choose the first four jokes.
We MUST choose the 6th joke as the only 1 remaining joke.
That's 1*5*4*3*2*1 ways to choose the five jokes.
 
Answer 1*5*4*3*2*1 = 120 ways.

Edwin