What does 1 Thessalonians 4:16 mean?

When the Lord comes down from heaven, there’ll be a loud command, the voice of an archangel, and God’s trumpet will sound. Then those who died trusting in Christ will rise first. 1 Thessalonians 4:16 - Modern Text Bible

(Paul describes a dramatic, unmistakable return of Jesus, where the dead in Christ are raised before anything happens to the living.)