How to use Google Spreadsheet without any extensions?

[Still-learning]

Use Google script.

Google Sheets and Apps Script

Disclaimer. My english sucks. Because I WANT to use Google Sheets !!! When I think about using Google sheets along with my application, I want a few basic things. They are adding (and possibly removing) rows and columns, reading (and possibly replacing) values ​​in the required cells, and doing these things from my app. Yes, I want custom API for my app, with blackjack and hookers! Is it really that hard? It took me a week to find answers and compile all information, i want to share with you n…