One way to do it is to set its position in the Initialize() method. Something like:
protected override void Initialize()
{
spritePosition = new Vector2(100, 100);
base.Initialize();
}
to give it a position of (100, 100).
If you want it in the center of the screen, you can use the Viewport property from the GraphicsDevice to get the dimensions of the screen, and use that to position it in the center:
protected override void Initialize()
{
int screenWidth = GraphicsDevice.Viewport.Width;
int screenHeight = GraphicsDevice.Viewport.Height;
spritePosition = new Vector2(screenWidth / 2.0f, screenHeight / 2.0f);
base.Initialize();
}
