SPOILER WARNING
What we know:
Thanos trades an army for the Infinity Guantlet
Loki gets the Army
Loki invades Earth
Loki fights each of the Avengers
Loki gets into Sheild custody
Speculation:
From what I have seen, most people think that Loki starts in custody, what if that is after the fight on the streets?
LOKI's chain of events:
Loki gets army, gives Guantlet
Loki invades earth
Loki fights on streets
Loki loses, goes to sheild jail(end of first half of film)
In the second half, we have Thanos figting a weakened earth, attempting to destroy for death.