The future
When discussing the future using a continuous tense we recycle the present continuous tense. It is often used to ask about and discuss future arrangements or plans with just the addition of a future time, but you only use it when these arrangements are certain.
For example:
Q) What are you doing next week?" A) "I'm working."
Q) What's he doing tomorrow?" A) "He's playing tennis."
The present continuous tense is also used to talk about and make future appointments and arrangements using the words go or come....
For example:
Q) When are you coming to see me?" A) "Next week."
Q) What are you doing tomorrow?" A) "I'm going to the dentist."
...and using verbs of arrival and departure.
"We're arriving in London at 2.30."
"The train leaving from platform one is the 2.45 to Edinburgh."
The Future Continuous (will be doing)
The use of 'will be doing' in a sentence is often referred to as the future continuous. It is used to talk about activities that will be happening at a particular time or over a particular time in the future.
For example:
Next week we will be having a party. Can you come?
You can also use it (or the present continuous form) to talk about future plans.
For example:
We will be leaving here at 7.30pm.