1. put your hands up
He said, Reach for the sky, and I put my hands up
To 'reach for the sky' is a colloquial way of asking someone to put their hands up, usually as a sign of surrender. This is a slang phrase which you will often hear used in movies or stories.
2. be ambitious, believe in yourself
if you reach for the sky, you can achieve anything
same as Reach for the Stars