App Developer who can develop a home service app based on Dart language in Flutter

We are a solar consulting firm and we are looking forward to hire an App Developer who can help us to develop an application based on Dart language in Flutter and should be running on Android, Web & IOS. The Application will be a kind of Solar Operation & Maintenance service App which will be similar to home services application such as Urbanclap & Gomechanic interface and UI/UX. We need a freelancing support for installation of full set up and any further support whatsover needed.