Here is a description from the walkthrough writers of how to complete the level as well as earn some other achievements along the way:
Head right, jump over the gap as Rey, enter the scan area and scan back left for a target to shoot. Hit it to give Chewie a platform. He can then pull on the handles at the top of the stairs to bust the box apart. Multi-build left and pull on another set of handles. Switch to Rey when prompted to head up the steps and then use her staff to get over the gap. Head right to the block that needs pushing. Push it to the end and then switch to Chewie. Smash the multi-build and rebuild right. Have Rey push the rock the rest of the way, and then Chewie can build himself a couple of platforms from the pieces.
Shoot the target to the right and build yet more handles. Pull them and build the resulting debris. Head up the steps and then all the way around to the right until you reach some handles next to a pile of rocks. Pull them. Send Rey left and down and use the staff in the slot to create a series of swing poles. Head across and up and then back left towards Chewie. Smash up the shiny debris and build a staff point. Winch it around to clear the blockage from Chewie's path. Both characters can then push the big vine-covered rock off the edge of the cliff. Have Chewie pull out another set of handles and then send Rey all the way up to the finish.
Here is a video walkthrough:
Credit to packattack04082.