Unlocking this level requires a minimum of 10 Gold Bricks and is located in D'Qar. The walkthrough writers give a good descriptive guide:
Once in the garbage, head left and smash the shining object. Multi-build right. Head across the swampy part of the area to the right and have Poe and Ackbar pull on the hooks. Have Ackbar head into the pool. Build the pieces he finds into a BB-8 pad and send the little guy over to the far platform and solve the lock puzzle over to the left.
Have Poe pull down on the hook above him. Multi-build left and have BB-8 access his switch. Send Ackbar forward and into the pool. He can then pull on the lever on the far side. As Ackbar, head right and smash the shining object. Rebuild a BB-8 pad and put him on it. Pull the pipe left. Next, smash the shining object on the left of the area to build a staff point. Ackbar can use these like Rey, so pull the bridge up. Once 3P0 is standing by the back platforms, multi-build to the right and step on the button. When he's on the first platform, smash and rebuild up (in the middle) to get him over to the next platform. Finally, smash and rebuild left to get him onto the lift. Smash it to send him up. Access the 3P0 panel to get out of here.
Follow the corridor and have BB-8 solve the lock puzzle. Keep going and deal with the Stormtroopers, and then go into the red-lit left area and grab a black helmet with red stripes from the hat machine. Access the panel in the centre of the room. Keep going round to a Blaster Battle. Deal with the first wave and move up, then deal with the second. Switch to Poe when he moves up top so he can release the Wampa by shooting the target. After the Battle, head to the top right corner of the area and smash the shiny block. Build a push block and push it to the back wall. You'll head down the lift. Deal with the enemies and then head into the left doorway.
Get through two on-rails flight sections and then take out 15 TIE fighters. Then grab three pink missiles and blow up the three large clusters of rocks with pink gems on them. Job done.
Here is a video walkthrough of the level:
Credit to HappyThumbsGaming.