YOU SAID:
My dad ledt to get the milk from the store
INTO JAPANESE
父は店に牛乳を買いに行きました
BACK INTO ENGLISH
Father went to the store to buy milk
INTO JAPANESE
父は牛乳を買いに店へ行きました
BACK INTO ENGLISH
Father went to the store to buy milk
That didn't even make that much sense in English.