Unlocking this level requires a minimum of 20 Gold Bricks and is located in Jakku. The walkthrough writers give a good description on how to complete the level:
This whole first area is a big Minikit treasure hunt so for Story purposes just head all the way right and deal with the enemies. Smash up the brown and yellow console at the back to grab a wheel. Head left as directed and place the wheel in its socket. Turn it to set up the bridge. You'll now have to switch to Athgar Heece, the only Jetpack character in the base game, and boost up onto the bridge and the following platforms, bringing him back round to the right but now on the second level of the building. Once you've sidled around, smash up the brown object to build a ladder for Lor San Tekka. He can then pull the grapple around to the right of the second level. Athgar can then throw a thermal at the silver debris. Switch to Lor and turn the crank with his staff. This will open the door to the next area.
In the next area, jump up to the swing pole as Athgar (it has to be him - although Lor will attach himself he'll immediately detach when you switch characters). Switch to Lor and have him turn the wheel. When Athgar is pulled up to the top, switch to him and launch onto the platform. Deal with the enemies. Head into the foreground and smash up the debris on the right of the push block to reconstruct the push block's path. Shove it down and rebuild the mess into a staff socket. Lor can then use this to turn the bridge into a wind buffer. Use Athgar's jetpack to clear the gap. Deal with the enemies and then blow up the silver part of the crashed spaceship to make a route for Lor. Head all the way right and pull on the grapple to make a bridge.
As Athgar, destroy the silver object that is spinning fast between the two trapped mechanical beast things. Get on one and use it to smash the cracked wall on the right. Bounce up to the new area as Lor and scan the back panel to reveal a silver section, which Athgar can then destroy. Now head all the way over to the left and scan the wall as Lor to reveal another wall crack. Get on a beastie and bash it down, then hop up the wall-jump as Athgar. Push the block along its path to send it down to Lor who can build himself a ladder from the debris. Up top, use Lor's staff on the crank to the right to smash up the central box. Jump back down and build a jump pad in the center, allowing both characters to hop up to the end of the level.
Here is a video walkthrough of the level:
Credit to HappyThumbsGaming.