Read 'how to guide' and set PHP max execution time on cPanel. A quick step by step guidelines for new learners.
If you are running into problems uploading files on your cPanel server, you can easily adjust the PHP settings to allow a longer execution time.
To do that go to WHM -> Service Configuration -> PHP Configuration Editor
You will see the option
Set the value to the number of seconds you wish on both of those (an explanation of both is provided)
Click 'Save' at the bottom
You will also need to restart Apache after changing the configuration.
Go to WHM -> Restart Services -> HTTP Server (Apache)
Click 'Yes' to restart.