Stuck on Setting Up Webpack with React - reactjs

Question

I've tried looking at the docs and searching online, but I'm having a really hard time configuring webpack with my React project. I'm trying to use webpack-dev-server. When I do the yarn start command, this is what I see in the browser.
Image of what I see in the browser
I have no idea where to go from here. This is what my webpack.config.js looks like.
const path = require("path");
module.exports = {
entry: './src/components/app.js',
output: {
path: path.resolve(__dirname, 'dist'),
filename: 'bundle.js'
},
devServer: {
contentBase: "./dist"
},
module: {
rules: [
{
test: /\.js$/,
exclude: /node_modules/,
use: 'babel-loader'
}
]
}
};
Here is my package.json
{
"name": "react-portfolio",
"version": "0.1.0",
"private": true,
"dependencies": {
"react": "^16.2.0",
"react-dom": "^16.2.0",
"react-router-dom": "^4.2.2",
"react-scripts": "1.1.1",
"source-map-explorer": "^1.5.0"
},
"scripts": {
"analyze": "source-map-explorer build/static/js/main.*",
"start": "webpack-dev-server --open",
"build": "webpack",
"test": "react-scripts test --env=jsdom",
"eject": "react-scripts eject"
},
"devDependencies": {
"babel-core": "^6.26.0",
"babel-loader": "^7.1.3",
"babel-preset-env": "^1.6.1",
"babel-preset-react": "^6.24.1",
"webpack": "^4.0.1",
"webpack-cli": "^2.0.9",
"webpack-dev-server": "^3.1.0"
}
}
Any guidance would be greatly appreciated.