js/cordova notepad?

Question

JavaScript

You need to make a notebook. On html5, js, cordova. Just a person presses +, a note is added, when you click on a note, everything else is hidden. And a product window appears, when a person clicks on add a product, a pop-up appears with products in the form of a list, a person clicks on the right one and he gets into the list.
Actually what is the question. How to save all this? How to hide the rest of the blocks when choosing the right one? And how, when choosing the right product, add it to the block. Or is it better to do everything on separate pages?
I don’t know how to implement it at all, but the deadline is already :C