Future Perfect
Use:
The future perfect is like all perfect tenses.
It is used with since, for, already, so far, etc…
l___________l_____________l
Now Action in the future Action after the future action.

Structure
An important note is the structure of the 3 person singular.
She/He/It will have been….

Statement:
Subject + will + have + past participle.

Negative:
Subject + will + not + have + past participle

Interrogative:
Will + subject + not + have + past participle

Examples:
Alex will have been at the company for 5 years next June.
The managers will not have met the client before the meeting.
Will Arnold have seen the plans before the construction begins?