The cube will fall into the ditch. Use the portal gun to get it out. Put it on the button.
One cube is in the ditch, do the same thing from last room. The second cube is above. Shoot a portal so you get up to the orange portal, shoot a portal behind the cube, then enter the orange portal to get it.
Shoot a portal to land on top of the glass roof above you.
Put your portal above the receiver so the pellet bounces into it.
Portal onto the moving platform and use portals to bounce the pellet into the receiver. The platform will move you to the exit.