This articles explains VESA Mounts
The Flat Display Mounting Interface (FDMI), also known as VESA Mounting Interface Standard (MIS) or colloquially as VESA mount, is a family of standards defined by the Video Electronics Standards Association for mounting flat panel monitors, televisions, and other displays to stands or wall mounts.
A good guide is HERE
Please report any broken links by emailing support@elotouch.com and include a link to the knowledge article