Provide the theme summaries for the following conversation: 

Luka: Mum!
Luka: I'm trying to read your instructions for the meal but can't understand a thing.
Emily: What's the problem this time?
Luka: What did you mean by preheat the oven?
Luka: Well I know what you meant by that but to what temperature?
Emily: 180 degree like always.
Luka: It's the first time I'm making this by myself!
Emily: Don't worry, it's really easy.
Emily: Just preheat the oven to 180 and put the dish for 30 minutes.
Luka: Okay, I'll try.
Emily: Just remember to cool it off after taking it out of the oven. You'll burn yourself otherwise.
Luka: Will do. Thanks!

Summary: 
Luka doesn't understand his mother's instructions how to prepare his meal. Emily advises him to preheat the oven to 180 degrees and warm the dish for 30 min.