This is one of the trickier tenses in the future tense.
Its forms is:
S (I/You/They etc.) + will + be + verb-ing
So how do we use the future continuous?
1). The future continuous is useful at stating whether or not you will be doing something at a future time, or to ask someone what they will be in the middle of doing at a certain time in the future:
I will be doing my homework at 6, don’t call me; We’ll be eating lunch in the cafeteria, come and join us; Sir won’t be in his office after school today; What will you be doing tomorrow afternoon?
2). It can also be used with the past continuous to compare the past and the future:
I was sleeping at this time last night. The same time tonight I’ll be dancing; we were in Thailand this time last year watching the sun set. Next month I’ll be in Australia doing the same thing
3). And to talk about an action taking place because of a routine or arrangement:
I’ll be playing football tonight. I play every Wednesday; Mum will be arriving from Portugal in ten minutes
Playing football is part of the person’s routine whereas Mum arriving from Portugal is something pre-arranged, so is an arrangement.
4). We also use it to ask about whether what someone is doing fits in with their wishes. It can be seen as a polite way to ask for something the speaker would like:
Will you be seeing Granny today? Why? Because I need you to give her this
When will you be heading to Zimbabwe? Tomorrow, why? Because I wanted to see you tonight
How long will you be using the pump for? 5 seconds, why? Because I need to pump up my ball