It is the future perfect tense.
Formation
futur antérieur = auxiliary être/avoir + past participle
in simple future of main verb
eg. 
j’aurai fini nous serons allés
NOTE: With auxiliary être, the past participle agrees in number and gender with the subject.
Usage
Futur Antérieur is used for an action that is completed before another action in the future.
Translation into English
It is usually translated into English as “will have + past participle”.
eg. j’aurai fini – I will have finished
Negation
Negation is formed by placing ne /n’ …. pas around the conjugated verb or the auxiliary,
eg j’aurai fini – je n’aurai pas fini
Conjunctions
In French, future antérieur is used after certain conjunctions like
quand - when lorsque - when dès que - as soon as aussitôt que - as soon as