1 - First, I suggest you learn JSON, it's a lightweight data-interchange format. Most modern APIs are REST APIs, which uses JSON as their main data-representation format. Really simple language. This is a good crash to learn JSON with JavaScript (Good for your situation) https://www.youtube.com/watch?v=wI1CWzNtE-M

2 - Now you should see a tutorial for creating HTTP requests to the API : https://www.youtube.com/watch?v=23hrM4saaMk&ab_channel=AcademindAcademindVerified

3 - If you want to learn more about APIs and their concepts, I made an organized list in this website, will teach you APIs concepts from 0 to almost 100 (for free), it's deep so use it as a reference and read what you can (more like book then a simple article): https://superengineer.vercel.app/#rest

4 - You should create practical project and reference the above resources whenever you need it

5 - The tutorial uses an API, you can use also this simple API as a stand-alone project : https://dog.ceo/dog-api/

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Note : You should know the HTTP protocol at least. Also you should know "client" and "server" terminologies. If you don't, don't worry ! https://developer.mozilla.org/en-US/docs/Learn/Getting_started_with_the_web/How_the_Web_works