it's similar to saying 'but'.
I was going to go, but it turns out i'm busy.
I was going to go, it turns out i'm busy though.
It's the same if you are responding to a question.
Person A: Are you coming tonight?
Person B: i would, but i'm busy with homework.
Person B: I would like to, i'm busy with homework though.
Person A: I already finished mine! It didn't take too long.
Person B: but i'm not as smart as you.
Person B: I'm not as smart as you though.
Sometimes it sounds more normal to use 'but' and sometimes it sounds more normal to use 'though'. It's hard to say the exactly rules but you can just think when someone says 'though' it's like they are saying 'but'.