The manual is shown in the document in the link: https://d2v0huudrf11kh.cloudfront.net/vevor-center-goods/%E6%9B%B4%E6%8D%A2%E6%9C%BA%E8%AF%B4%E6%98%8E%E4%B9%A6%281%29_1650335265376.pdf
For after-sales information, refer to this link: https://www.vevor.com/pages/contact-us
By vevor