Questions on License

[LIUYOU2015]

Hi, thanks for this great APP. I'm interesting in extending this APP to something like a timer + to-do list. I might submit my modification version to App Store (for profit if possible).
Since this repo uses MIT License, there's no restriction on copy, modify and sell it. The only condition is that

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

Is my understanding correct?