Ich werde morgen ankommen.
Ich werde morgen angekommen sein.
Please explain to me in a concrete way how to use Futur 2 when Futur 1 is not usable. I'm really confused and the Internet isn't helping.
Ich werde morgen ankommen.
Ich werde morgen angekommen sein.
Please explain to me in a concrete way how to use Futur 2 when Futur 1 is not usable. I'm really confused and the Internet isn't helping.
Futur II and Plusquamperfect are dependent tenses. You only can use them if you have two events, and the places, where these tenses feel home and comfort are subordinate clauses:
Wenn du heute Abend heimkommst, werde ich bereits eingeschlafen sein.
When you come home tonight, I will have already fallen asleep.
Wenn du heute Abend heimkommst
This is the main clause. Grammatically it's in Präsens, but Präsens also can express events in the past or in the future, like in this case. Coming home is an event in the future.
werde ich bereits eingeschlafen sein
This is a subordinate clause. It only makes sense together with the main clause, because the main clause provides a point in the future to which the subordinate clause refers. The subordinate clause talks about a moment that will be in the past at this reference point. The moment when I fall asleep will be in the past when you arrive at home.