POSTING PROBLEM

I want to write an article and have it posted to my website. If the article is too long, I would like to shorten it by having “to continue reading on…” at the bottom of my article so that the reader can click on “to continue reading on…” and read about it under a different category on my webpage. How does this work?

Please understand I am new to this and I need very clear and precise directions when helping me. This is like a foreign language to me. I have tried reading up on it (wordpress) but it does not always help.