To make the automation framework in selenium is an art which you can learn with time, after having a vast practice. It also depends on your application and its functionally for the time being you can practice building a hybrid framework.
You should start building it from scratch:-
Start creating all the necessary packages like your Excel library, Utility and POM.
Then you should try to create some common function to handle some common action like alert handling, Login, logout and navigation from one page to another.
Introduce TESTNG to Report generation, parallel execution,group execution.
If you want to learn Selenium you must take up the following Selenium Training Course. You can also watch the following Selenium video tutorial to learn more. .