subject + will + be + verb-ing
Don't call at 9 o'clock - we'll be having dinner.
This time next week I'll be sitting on the beach.
I'll be working late every night next week.
Will you be coming to the party?
Actions and events in progress / incomplete at a specific time in the future
The future continuous can refer to actions that will be in progress at some specific time in the future; i.e. actions that have already started but have not yet be finished.
In example (1) you will start dinner before nine and finish dinner after nine.
In example (2) You will start sitting on the beach before two o'clock and finish sitting on the beach after two o'clock.*
*'This time next week' means the same time next week as it is now. So if it is now two o'clock and today is Thursday, then we are talking about two o'clock next Thursday.
NB Some grammar books only mention this use. However, the uses described below are very common also.
Future actions that continue over a period of time
The future continuous can emphasize that a future action will continue over a period of time:
We'll be working on the cover design next week.
This emphasizes that the work will continue over the week.
In this course we'll be looking at some more advanced grammar points.
You will be looking at them during the whole of the course.
In both of these examples, you could also use be+going to or present continuous. However, the future continuous shifts the emphasis to the continuation of the action over the time periods mentioned. (The present continuous emphasizes an arrangement; be going to emphasizes an intention.)
Future actions that will definitely happen at some time within a time period
I'll be seeing Peter some time tomorrow.
We'll be discussing the sales figures in the monthly meeting.
In both of these examples, be+going to or present continuous could be used. The future continuous emphasizes that the actions will happen at some time within the time periods mentioned.
Making polite enquiries about future intentions
When asking questions about people's future intentions, the future continuous is less direct than other future forms?
Are you coming to the meeting?
Will you be coming to the meeting?
The first sounds more direct, perhaps because it uses fewer words.
Such forms are common in a service setting, such as a hotel.
Receptionist: Will you be having breakfast, Mr Foster?