first it depends according to his / her experience within the same filed of the company he / she joined , then he must be hungry for knowing everything about the company and according to that he / she is the only one can manage the time for that , but as the normal employee it takes3 to4 months but he/she must making new creativity within these period to proof for the top management he / she not only willing to know but want make new procedure's to improve the work cycle within the company through a lot of ways.
If he has good accounting knowledge and experience in same industry,it need2 weeks to1 Months....Just to familiar with work atmosphere,files,and accounting software...
in case of lack of knowledge or experience,time will take according to his grasping power adn hard working but minimum it needed2-3 months.....