Add explanation on how this program works.

README.md

@@ -12,6 +12,11 @@ Download Xcode and other developer tools up to 16 times faster with resume capab
 - ✨ Resume download automatically if the download failed due to any reason.    
 - ⏬ Multiple downloads supported.
 
+### How does it work?
+Basically, this program is completely dependent on [aria2](https://aria2.github.io). `aria2` is a utility for downloading files that support segmented downloading. When we start downloading, this program takes the download auth token from cookies (as well as other required parameters), and pass them to `aria2`.
+
+An instance of [Process](https://developer.apple.com/documentation/foundation/process) takes the output from `aria2` and shows it on UI. You can achieve the same with `aria2` without this program, but you'd have to manually take out the auth token from cookies and other parameters and feed them into `aria2`.
+
 ## Installation
 
 #### Using curl
@@ -20,6 +25,7 @@ Now, you can install Downloader by running the following command in your termina
 ```bash
 curl -s https://xcdownloader.com/install.sh | bash
 ```
+
 #### Manual
 If you face any issue using the above command then you can manually install it by downloading it from [here](https://xcdownloader.com/download). After that, unzip Downloader.app.zip and move Downloader.app into the /Applications directory.
 
@@ -47,7 +53,6 @@ If you face any issue using the above command then you can manually install it b
 ## Contributions
 Any contribution is more than welcome! You can contribute through pull requests and [issues](https://github.com/vineetchoudhary/Downloader-for-Apple-Developers/issues) on [GitHub](https://github.com/vineetchoudhary/Downloader-for-Apple-Developers/)
 
-
 ## Bugs
 Please post any bugs to the [issue tracker](https://github.com/vineetchoudhary/Downloader-for-Apple-Developers/issues) found on the project's GitHub page. Please include a description of what is not working right with your issue.