Convert a Template to a Website

In short I need to build a online service that lists information drawn from a database. I have some raw sample information in Excel at the moment and have built a very simple manual model around it already. I need to upgrade this to be converted into an online searchable database. The site needs to be able to hold users that can log into the site or app to get the information. Users can view information that have been input and sign up for a particular or multiple of these input and the service needs to summarize some cost information based on what users sign up for and provide a dashboard with a summary of selected items by calendar dates with some basic information including cost. It needs to be able to integrate with online and smart phone calendars, in line with a typical fitness booking app. I need to build a demo version to a level where I am satisfied that I can bring on beta users and have a minimum viable product. There needs to be a website and a mobile app version with same functionality.