How to simply add a new object to a page variable list of objects as sequential index?

I have a page variable list of object with two properties:

paragraphsList:
… index
… content

I have an input repeated with the pargraphList variable.

I have an input under that whose value is set to page variable currentParagraph (text). This is the input user writes in first.

I have a number variable paragraphIndex set to 0 as initial value.

I have a check mark for user to click when they are finished and want to add the first paragraph.

How do I simply add the first paragraph text to the paragraphList with index 0, which is the initial value of the paragraphIndex. All subsequent paragraphs need to be added directly under the last one.

In java this is real simple, simple add item to map string of code.

I have tried INSERT_ITEM_AT and it will not work with just a string of text.

I am trying to allow users to write a long article. When I try with just a single input, the input disappears after user writes too much. Some bug or something which only allows a certain number of characters in a single input, I dont know, but I need to create a way for users to be able to write a long article and the Rich Text Editor just will not do because of the words “Rich Text Editor” which appear on top cutting off the cancel button halfway which makes it look like the app is very unprofessionally designed.