Customers who have been renovated know that the window friction stay is used to connect the window sash and the window frame, and the link-type movable link device that enables the window to open and close. The friction stay generally includes a sliding rail, a slider, a supporting arm, a long cantilever, a short cantilever, and an inclined cantilever, wherein the sliding block is mounted on the sliding rail, the long cantilever is hinged between the sliding rail and the supporting arm, and the short cantilever is hinged. What is the installation method of the window friction stay between the windows?