This is the wiki for most of the technologies we use at Hack4Impact, covering all sorts of information you will need to start developing along with some formal and explanatory documentation. You should be able to find most of your questions here. We generally use Flask to build our backend REST API service, Postgres as our persistent data store and React as our Frontend Library. If you run into problems with React, be sure to check out this first.
First, you must install and setup Python and Node.js on your computer. Follow Mac Setup or Normal Windows Setup depending on what OS you have. You will need to understand the Bash Command Line along with Git and Git Flow for version control and Team Development Collaboration. In addition, read up on Development Guidelines.
We've also used GraphQL for the Backend to eliminate underfetching/overfetching and MongoDB with React and Relay.