How to start creating a chrome extension or an app to track prices in an online store?

Question

Programming

Tell me where to start, I want to make a browser extension or an application, but I don’t know what exactly, to make it easier for a beginner, regardless of technology, because I will study it as I solve the problem (for self-study purposes).
The essence of the task:
-track the prices of any product from a particular online store, for example computeruniverse
-monitor price changes, if the price has been changed, then build a graph with price changes
I suppose if this is an extension for an Internet browser, then the technologies that need to be used , these are php and javascript, and if the application, then it depends on the platform, i.e. for example, if on android, then java, etc.?

Answer 1

You should always start with setting the task, goals and TK.
And based on these data, technologies, languages, and so on are already selected.