If you right click on the Canvas Tab and select Calibrate, you can click on a point, say a top of any Piece and then click the bottom and input a size you would like your pieces to be, the King and Queen being Taller so these would be a good option for calibration, I will make the king 50mm in height, this should be fine, the other pieces will match as they are on the image from a perspective point of view.

Save the Image to a place where you can easily find it, and then using the Insert tab in Fusion 360, select canvas and highlight the plane, get the image to a size where you can easily see the edges of the pieces, and set the opacity to around 65%.

The next process is have a look online at some front view images of chess pieces and opt for an image which has good clarity and is totally flat that is not on any angle most are slightly off-set but its only a guide anyway.

In Fusion 360 we always start by creating a component then create sketch, in this instance we are selecting the front plane.