The description sounds a bit odd, but all models are different. Double check that you have the correct manual. I couldn't find any free ones for the 505 model, only pay versions.
What exactly does the manual say? Some White models have a lever to the right of the bobbin case, some where bind the lid in the freearm. It could be a knob some where on the machine, but I didn't see anything obvious from the exterior of this model. If the accessory box is complete check if there's any feed dog cover (small metal plate). Some models have function for raising and lowering the needle plate.