Form and rules
How it works
Form the future continuous with will be + -ing and use it for an action in progress at a future moment.
Future continuous can also describe an expected course of events and can make questions about plans sound less direct.
Form the future perfect with will have + past participle for something completed before a future deadline or reference point.
By + future time often signals future perfect, but always check whether the meaning is completion rather than activity in progress.
For duration continuing up to a future point, future perfect simple may describe a state while future perfect continuous can emphasize an ongoing activity.