How does the radio of Pioneer Desktop Audio store the memory radio?

Pioneer desktop audio storage memory radio is not very convenient, and the explanation is relatively simple, which is generally difficult to understand. Take Pioneer X-HM2 1V-S desktop audio as an example. The instructions say that after adjusting the desired FM, press the memory key, then choose where to save it, and then press the memory key. But this memory key, like other numeric keys, is unresponsive when pressed directly. You must first press the SHIFT key without letting go of your hand, then press the MEMORY, that is, the saved position number, then press the preset key+or-to select the digital position to be saved, then repeat the SHIFT key without letting go of your hand, and press the MEMORY at the same time, and several "saved position number+stereo" will appear. For example, if you save in the position of 3, it will be displayed as 3 stereo, and you will be successful, and then shake it directly. Pioneer's manual only introduces the function of the SHIFT key on the remote control: one key has two functions, and you must press the SHIFT key first when choosing one of them, but it is difficult to understand the specific operation when storing the radio operation.