Hi
Please note that we do not map stalls or businesses without a proper permanent structure.
That being said, since the place is already inside Google Maps which is how you are able to navigate there using Waze, you can also do the necessary changes inside Google Maps.
However, if your stall is a permanent one then you may also add it into Waze using the Report > Place option.
Please follow the guidelines in Place Update Request Guidelines - Malaysia / Place Update Requests - Waze Discuss when creating it.
Thanks