What does 'to know the ropes' mean?

English Language Tests, Intermediate level

ESL/EFL Test #289 [color=blue]“English Slang Idioms (11)”, question 7

“Once you know the better, we will give you more responsibility,” the boss said to the new trainee.

(a) lines
(b) slips
(c) straps
(d) ropes

English Language Tests, Intermediate level

ESL/EFL Test #289 [color=blue]“English Slang Idioms (11)”, answer 7

“Once you know the ropes better, we will give you more responsibility,” the boss said to the new trainee.

Correct answer: (d) ropes

Your answer was: [color=red]incorrect
“Once you know the lines better, we will give you more responsibility,” the boss said to the new trainee.
[size=200]_________________________[/size]

Does the point of it go that once he get to know with the matter of his work better He will get more responsibility?

That is right.

“to know the ropes”=

to understand the procedures and processes necessary to perform a task or understand a situation