I must be missing something here. What preview are you talking about? Did you run the model locally? Could you elaborate what you did? Preview mode in the modeler is simply there to show you how things will look like and not usable to enter data. You must run the model for that.
Hello Ronald, actually, due to technical errors, The data that I uploaded on the pages i created with an add button to upload data, did not reflect in the preview of the app i was making. It now reflects there. I guess it was a technical error. Thank you for reaching out to help :)