Remove the silver retainer bar and cardboard boxes attached to the base. MATTRESS FIRM 600 Manuals Manuals and User Guides for MATTRESS FIRM 600. STEP 1: Unpack the adjustable base by carefully cutting the plastic bag to remove the adjustable base. We have 2 MATTRESS FIRM 600 manuals available for free PDF download: Owner's Manual, Setup Manual Unfold the base carefully as the parts for assembly may have shifted during shipping. See Components for Assembly and Operation on Page 8. Experience an unparalleled night’s sleep on the best adjustable bed the Mattress Firm 600 Adjustable Base. The head and feet up positioning may relieve aches, and the 3-massage setting could help relax your muscle and help you unwind after a long day.