Angular http request - where in files?

So i need to build a full website for my homework project. Its MEANstack. Currently im a little bit struggling with learning Angular. (7).

Ive created some pages, and i have a properly working router. The thing is, ill need my angular client to query my node.Js server using an API., And i dont know where (in which file exactly) to put the http request code?? I mean, every angular component has more than 1 file, so, where?