To your right, there is a moving platform. Parts of the ceiling above the platform are white. Put a portal on one of these. Now go over to the blue gel and jump. You'll start bouncing. Go up to the ledge above.

Put a portal of the opposite color on the wall in front of you. Look through and drop in when the moving platform is there. There is a cube in the wall next to the platform. Pick it up, then fall to the floor. Go back over to the blue gel and jump up to the ledge.

Put the cube down and turn around. There is a red button on the other side of the room. Make a portal on the wall near that button, then a portal of the opposite color on the wall near you. Take the cube through and put it on the red button. This opens a white wall (follow the orange dots from the red button to find this wall).

Put a portal on that wall. Now put a portal of the other color on the white wall on the ledge. Jump to that ledge and go through the portal. You'll fall onto the blue gel. Bounce over to the emancipation field on the opposite ledge. Go through.

Bounce sideways onto the blue gel on the wall. You will be bounced from side to side all the way to the end of the room, where you can get a cube. Pick up the cube, then go back to the opposite ledge (if you go to the floor, be careful of the big hole.) Put the cube on the red button. Now go back through the emancipation grid.

Now there is a second white wall that you revealed by putting the cube on the red button. It's to the left, up on the wall. Put a portal on it. Then put a portal of the opposite color on one of the walls down below. Bounce over to that wall and go through the portal. You'll come out from the higher portal and bounce on the gel. This should put you on the ledge with the exit. Go through. Follow the path to the elevator.