You are booking into a hotel.
Elements:
Book into the hotel - you have a reservation.
Complications:
You are on your own.
You want a shower.
You want breakfast in the morning.
You have an early meeting and must not be late.
Student B
You are a hotel receptionist.
Elements:
Welcome the guest.
Find them a room.
Complications:
You can't find their reservation.
You only have a double room with bath available.
Before writing the whole dialogue, perhaps you need to watch an example. You can have a look at this Blog for Tourism.
However, still unable to start writing any line, here's some useful vocabulary on Hotels.
For further practice you can also watch and fill in these vocabulary activities:
Many things about the English Language
The Hotel Room of the Future, by frenchfrog
Find this and other travels exercises in English Exercises .org
Finally, let's watch this You Tube video on vocabulary.