Here are the steps to completing it without trying to explain exactly where to place each portal. You’ll portal through the pillar and land on the exit on the other side. Place a portal on this side of the pillar and take a running jump once more. Place portal on the wall and go through back to the start of this chamber. Walk around to the other side and portal up to the walkway above. Place portals under the blue gel and on the roof at the end of the platform. Press the red button to squirt a line of orange gel. Place a portal under the orange gel and the other on the pillar. There’s a platform with a pillar half way across the gap and the exit at the other side. This time you’ll find two gel dispensers, blue and orange, with red buttons next to them. Press it to open the exit and go through. Run through and you’ll end up flying up to the red button. Go through and place a portal at the start of the runway.

Place a portal under the red button with the arrow. Run along the ramp to bounce up to the higher platform. Place the cube on the button to lift up the ramp. Portal your way back to the start of the chamber. Place a portal behind the cube and one on the other wall. Go through the portal and down the second runway so you can jump across the second gap. Place the first portal under the gel dispenser and press the button. Go around the corner, place the second portal on the wall and go through. Turn around and place a portal above the ledge with the button. Run along the runway and jump across the gap. Press the button to spray gel along the runway. Place a portal under the orange gel dispenser and one on the wall at the start of the runway. The first chamber uses orange gel that you’ll need to use to run faster and get across large gaps.

Portal 2 bounce gel