LEGO Dimensions

In addition to the other solutions, using the Wicked Witch (or any other flying character/vehicle) to fly around and get you to other areas will make your task a lot easier. Once you get to a tricky platform, you can reload Chell and solve the puzzles.

This is a straightforward achievement, like all the other level completion achievements in this game. One thing to note, is there is a bug that can (as of 2015/10/4, with the Day 1 patch installed) prevent you from finishing the level. If you upgrade the Sentry Turret to level 2, you will no longer be able to use the Sentry Turret to activate Turret Switches. The level 2 Turret itself is unable to active these switches, but even swapping to the level 1 version does not allow Turret Switches to be activated. Until this is patched, complete all the Portal 2 DLC achievements before upgrading the Sentry Turret to level 2 (which has Gold Lego destruction powers! Not Silver, as the game says when you encounter Silver Lego).

EDIT: As pointed out on GameFAQs, you can get around this issue by creating a Default Toy Tag for the Sentry Turret. You will keep all your Sentry Turret upgrades, however the physical turret model will be reset to the original, non upgraded state, and be capable of triggering Turret Switches again. You can then switch back to your upgraded Sentry Turret by making a Toy Tag normally through the upgrades menu.

To get this achievement you must purchase the Portal 2 Level Pack, build Chell, place her on the portal pad, and when you enter the portal, you will be asked if you want to continue the story or play Aperture Science. Select Aperture Science, and play through and complete the level and you will win the Achievement. During the level you will be instructed to build the Companion Cube and Sentry Turret.