The German construction for explaining what your job is involves the German word for profession - "der Beruf". You have a choice of word order with this construction, and can also choose whether to say "ich bin Manager von Beruf" or simply "ich bin Manager".
You will have noticed that we use exactly the same construction for professions as we do for nationalities. wheras in English we would say "I'm a doctor", in German you would say "Ich bin Arzt" (literally - "I am doctor"). once more, the verb which you will need throughout is the irregular verb "sein".
And just as there are two words for "a friend" or "a German" depending on the gender of the speaker, there are also two forms of each profession which need to be learned to employ the feminine version of the noun if the person being described is a woman - "Ich bin Ärztin".
