Idiom – Know The Ropes
Meaning – to know how something works, to be familiar with a procedure, to understand how a system operates, to have experience in a particular area
In Context – Colin will be responsible for the new intern until he knows the ropes.
Origin – A nautical term, this expression originally meant that a sailor only had basic experience (i.e. they had only mastered the basic ropes).
Other usage – you can also say; show someone the ropes, learn the ropes, teach someone the ropes