This is the 14002nd most frequent Russian word.
объясняли
"Объясняли" means "explained."
In this interrogative sentence, "объясняли" is used to inquire if the action of explaining was performed in the past regarding the equipment usage.
Объясняли ли вам, как использовать новое оборудование?
Were you explained how to use the new equipment?
The past tense plural form of the verb "объяснять" indicating the action of explaining performed by the teachers in a past context.
Учителя объясняли новое правило грамматики на уроке.
The teachers explained the new grammar rule during the lesson.
Here, "объясняли" is used to indicate an ongoing past action by a group directed towards clarification of the document filling process.