How do i empty my bladder before bed so it wouldnt worsen my bladder which the doctor said it was distended?

Ask one's doctor: For girls and women, sitting down on the toilet, then relaxing the sphincter (muscles that keep the bladder outlet closed to urine flow), and let the bladder self-contract gently. The urine will flow out. For boys and men, standing up at the toilet, or sitting on the toilet seat, and then following the same relaxation of muscles as women do. If prostate is a bit big, urine stream slows down.