Need ideas to develop an app UI – Info Graphic Design

I’m a mobile developer (iOS and Android native). I have quite a bit experience but I am terrible with UI. I have an idea but I have no clue how to do the UI at all.

My idea is pretty much a mix of Trello + calendar + grocery list + expenses tracker. That’s mainly for personal purpose just to make my life organized and everything in one app.

Does anyone have any idea about how I should do this UI? Examples of something similar would be appreciated.

Also, you are more than welcome to work with me in this project. I will make it open source so unfortunately won’t have any compensation.