Enter terminal.
First install all relevant modules. In the main repo, enter 'npm install'. This will install all npm modules needed for the server-side (in package.json). Then, go into the client folder by entering 'cd client'. Enter 'npm install'. This will ensure that all npm modules are installed (in package.json).
To run the api: In the main repo, enter 'npm start' or 'node app.js'. This will run on port 8000. Then, go into the client folder by entering 'cd client'. Enter 'yarn start' or 'npm start'. This will start the client-side process. This will run on port 3000.
Enter localhost:3000 in the URL address bar of your browser. You are ready to go!