Moving 3D-Object In WPF HelixToolKit

Question

I'm new to HelixToolKit and I just wanna move the 3d object up, down, or forward after hitting the button. also need rotation, for rotation, I'm using the code below and it works fine.

        var axis = new Vector3D(0, 0, 1);
        var angle = 10;

        var matrix = dev.Transform.Value;     
        matrix.Rotate(new Quaternion(axis, angle));

For the moving object, I have no idea. tried the code below but it's not working.

        Point3D point2 = new Point3D(15, 40, 60);
        dev.Transform = new MatrixTransform3D(matrix);