Literally, this means striding or walking, but it seems a polite term to urge people to move, e.g., 请移步到餐厅用膳, shall we say "Please walk to the dining room for your meal?" It sounds very awkward, because unless there is more than one mode of movement(as in an airport you can either walk or take a bus to get to the aeroplane), walk should not be mentioned or even stressed here.
The term 移步 is related to an formal expression "请移玉步". It literally means "please move your noble feet" (asking a noble to move his feet is ground for apologizing). It is a polite phrase for asking someone to move from his current location to a new one.
请移步到餐厅用膳 means "Please relocate yourself to the dining room for your meal" (imply you are apologizing for the inconvenience)