How to fake it till I make it?

I've made about 4 or 5 posts asking about confidence, then I graduated highschool, and now I'm fine with how I look. Coincidence? I think not!

But more importantly, my issue now is I don't know how to speak to people. This isn't confidence it's just not knowing what to say. If you speak to me first I can respond easily but now I have a job interview and last time it didn't go well and I'm sure it's cause I didn't seem appealing. The place, McDonald's (they pay 20 an hour don't judge me, not like I care if you did), gave me a survey and called me a mentor and said I was 100% extrovert. So now I gotta figure something out before the interview happens and I remember this one guy saying fake it till I make it, but how can I fake it if I don't know how to fake it?

My plan for this interview is generic, compliment the interviewer in someway, answer the questions that make it look like I want to stay there, profit.

Question is how do I do it?

Tl;Dr I have an interview, I'm fine with how I look and accept that. Just don't know how to talk to people.