When taking blood pressure medicine or any other medicine that is prescribed by a doctor the doctor should state when and how to take the blood pressure medicine or any other medicine they prescribe to you.
It is recommended though that you do take your blood pressure medicine at night before you go to bed since taking the blood pressure medicine at night seems to be more effective at lowering your blood pressure and it's supposed to help reduce your risk for heart attacks and strokes when taking the blood pressure medicine at night vs during the daytime.