AVA241: How one knows to play on the manuals or pedals if the notation is not the usual 3 staves?

This question was sent by Jan, and She writes: Dear Vidas, Thanks for answering my question. I was just wondering how one knows to play on the manuals or pedals if the notation is not the usual 3 staves. Now I know! Last question...does that then mean that organists also have the discretion of playing other early Baroque pieces (such as Titelouze) on manuals and pedals. I always wondered how my teacher knew what to play when there were only 2 staves and I was asked to play with pedals.