How does one even conversation?

Not even joking, I've got this habit where I ignore people. Wait no thats sounds so bad haha. I just decide to reply at a later time then forget to. But nowwwwww I have a crush,(first like proper crush since highschool I think.) and I'm texting to that crush..... BUT I HAVE NO IDEA HOW TO TALK TO HIM. WHAT THE HELL AM I EVEN MEANT TO TALK TO HIM ABOUT.
MAJOR ANXIETY.