First make sure that you have both Mongodb and Node installed or it won't work.
Run the following command in your terminal:
git clone https://github.com/shikot0/Realtime-chat-app {Name}
This will clone the repository into whatever directory you are currently in.
The {Name} argument is the name that you want the repository to be saved as.
cd into the app directory and run the following command:
npm install
Repeat this process for the server directory.
Run the following command in both the server and the app directory.
npm start
This will start a react app and initialize the server. You may have to run the app and the server on a different ports, if something is already running on port 3000. If this is the case then you can modify the port that is being used by the server in the .env file and then do the same for the host in the API Routes Directory.
If you are still facing issues then repeat the process from step 1.