how to check blood pressure manually

{"title":"GB15979-2002 17in Blood Pressure Monitor Stethoscope 3mmHg Class II","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/89\/9e\/6dcf43e13b04ed21bc87c579a6a4-200x200-1.jpg","attrs":{"Brand Name":"Teveik","Model Number":"T-1029","Minimum Order Quantity":"10PCS","Delivery Time":"5-7 days","Certification":"CE","Place of Origin":"China","Payment Terms":"T\/T, Western Union, MoneyGram,Paypal,L\/C, D\/A, D\/P","Supply Ability":"50,000 pieces\/week","Packaging Details":"1pc\/box","Safety standard:":"GB15979-2002","Instrument classification:":"Class II","Display":"LCD digital display screen","cuff fits arm circumferences":"13 to 17 inches","Accuracy":"+\/-3mmHg","Stethoscope":"Single head stethoscope"}}