Dream About Working In A Dream

I dreamt that a classmate told me I could apply for a job when I’m sleeping. So you’re working while in a dream. It sounded weird but it was as if I had to, it sounded like I didn’t have a choice. Getting there was really weird, it was a tall building. You had to open a coffin and put on some sort of armour. And then you had two work phones. So then I guess you descended into the building somehow and fell asleep? But during your sleep you were working? I sat at a desk. Not many was at work. But my classmate and my twin was there and a teacher. I didn’t understand anything. It was like we had to solve math problems or something weird. Everyone knew how to do it and told me I would learn it eventually. And on top of that you actually got paid. My ex was then at the same table as me? He knew how to do it and it seemed he had been there a while. He tried to explain it to me but I didn’t get it. My excuse was that I was too tired and couldn’t listen properly. And then suddenly we had to climb a roof or something. He went first and waited for me to hold onto him but because of me we fell down the roof? The only way to be stuck to that roof was to put your nails in the roof but it was so tilted so it didn’t work. I didn’t understand this part of the dream?