Help me understand

I don't want to sound ignorant to the fact but this is my first time TTC and I have no clue really on what I'm doing. I just know that sex is involve and I said sign me up... jk that last part was a joke..... but forreal, can somebody please break down all of this TTC stuff for me? What are all the acronyms that I need to knowing? I also need to know exactly what bbt is and why it's important. How do I test for it? And when? How many times a month does this happen? I have irregular periods and want to be able to log/chart my bbt and be able to understand what's actually going on so I can help my fiance understand too.