Need help with my first Open Source Project

I'm trying to get started on writing my first open source project which happens to be a React Component. I've really been struggling understanding webpack when it comes to outputting the code for npm. I've been looking at other react-component projects most of the day and looking at the React & Redux repositories as well to try and glean what it going on. What I understand so far is:

1. I should have a directory in which I am building the files; in my case I have made this src/
2. This will be my entry for webpack.
3. The output will be another directory I decided to go with lib/ and I declare a filename: 'index.js'
4. My entry for npm needs to be "main" in the package.json so in my case "main": "lib/index.js"

Areas I'm getting super confused on:

1. Do I need to declare a filename or just output to my lib/ ?
2. In the package.json what is "file" doing? Seems like the files listed in the array are outputs for npm.
3. What is libraryTarget & library doing in the webpack.config? I continually see libraryTarget: 'umd' and I believe what it means is that it will build according to _universal module definition_.

My webpack as it stands at the moment looks like this (I have webpack-dev-server here because this is the development config for getting up and running):

'use strict';

const webpack = require('webpack');
const { join } = require('path');

module.exports = {
 entry: {
     bundle: [
         'babel-polyfill',
         'webpack-dev-server/client?http://localhost:9000',
         'webpack/hot/only-dev-server',
         './src/index.js'
     ]
  },
 output: {
     path: join(__dirname, 'lib'),
     filename: 'index.js'
  },
 module: {
     rules: [
          {
             use: 'babel-loader',
             test: /\.js$/,
             exclude: /node_modules/
          }
        ]
      },
 devServer: {
     contentBase: join(__dirname, './lib'),
     port: 9000,
     hot: true
     },
 plugins: [
     new webpack.HotModuleReplacementPlugin(),
     new webpack.NamedModulesPlugin(),
  ]
};

If anyone has done an open source react-component and has some insight on how to approach not just this; but the project in general I would be very grateful!