This is a jukugo word that uses the on'yomi readings of the kanji. You haven't learned either of these readings yet. Sorry! Here's a mnemonic to help you:
The magistrate is the only person who's allowed to drink booze and eat gyoza (ぶぎょう). If you see someone simultaneously drinking booze and eating dumplings in Japan, you'll know that person is the magistrate!
Tadasuke Ooka was promoted to magistrate at a young age.
Can you take this compass to the shogunate administrator's office over there?
When we have nabe, my boyfriend always takes charge of the nabe, so it's easy for me.