Immediately after the tribulation:
The sun will be darkened and the moon will not give light. The stars will fall from heaven. The powers of heaven will be shaken.
Then the sign of the Son of Man will come on the clouds of heaven with power and great glory.
The tribes of the earth will mourn
He will send His angels and with a great trumpet sound the angels will gather His elect together from the four winds - from one end of heaven to the other.
I not going to profess to be an expert in this area of end times. I wish I could explain it but I don't want to mislead anyone with my interpretation of it. However here are some basic things we can apply.
Be ready. Share the love of Jesus in Word and Action. He is coming back for us - have hope. Live the life He put in front of us with that hope in Him.
Watch. I think it will be a beautiful sight to watch unfold. He is Creator, He is Lord. Do not fear these things. Fear Him and put Him at lordship of your life.