1
general::
1. The intricate details of a situation or process. For example, It takes a newcomer some time to learn the ins and outs of the legislative process, or David really knows the ins and outs of how this engine works. This usage alludes to the tortuous windings and turnings of a road or path. [Second half of 1600s] 2. Those with position and influence and those without, especially those in office versus those who are not, as in "Juan stood well both with Ins and Outs" (Byron, Don Juan, 1823). [Mid-1700s]
American Heritage Idioms
2
general::
Phrase(s): the ins and outs (of something)
the correct and successful way to do something; the special things that one needs to know to do something. • I don’t understand the ins and outs of politics. • Jane knows the ins and outs of repairing computers.
McGrawhill's American Idioms And Phrasal Verbs