How is the process of mammography?

Patient's question:

My sister has been feeling a bit unwell recently. She has some hard small lumps in her breast. She had an ultrasound, but the doctor said she needs a mammogram to determine the cause. My sister is afraid of this test, worried it will be painful and that there will be wounds after the examination. I don't know what the process of a mammogram is like.
What kind of help I need: What is the process of a mammogram like?

Doctor's answer:

Mammography Examination Method
The advantage of mammography examination technology lies in its ability to detect breast masses and nodules that doctors cannot palpate, such as occult breast cancer and very early-stage in situ cancer, thereby improving the rate of early diagnosis. It can identify early-stage breast cancer two years earlier than experienced doctors, as only soft X-ray examinations can detect and diagnose early-stage breast cancer that presents solely as microcalcifications, which are difficult to identify clinically. Mammography is the best method for screening breast cancer and breast tumors. It primarily utilizes infrared technology to examine internal breast tissue abnormalities. Breast hyperplasia can also be detected.