Question

my job is to take charge of my administrator

Answer 1

كارم اينه كه [در نبود مدير] مسؤوليت اونو به عهده بگيرم.

The meaning of "take charge of" is:

(verb) to become responsible for a situation or person مسؤوليت كاري/ كسي را بر عهده داشتن يا گرفتن 

Example Sentences:

A: Our boss went home sick. What should we do?
B: I think I will take charge of our office. Everyone listen to me!

When my parents went on vacation, I took charge of my younger brother.