Lay the four sides of the crib on the floor in the way that they would fit together along with the parts needed for each side. This way you can make sure you have all of the parts and hardware necessary, and everything will be within easy access.
Attach the sides to the head end (the tallest side). Each side is marked "R" for right and "L" for left. Secure each side with two M6 bolts using the hex wrench. For this, you will use the longest of the bolts included that will range from 60 to 100mm depending on your model.
Using four 16 mm M6 bolts, attach the mattress support to the three-piece frame you have assembled so far, taking care not to scratch the crib posts. There are three positions for the mattress from newborn to a 35-inch-tall child. Secure the mattress support with the hex wrench making sure all bolts are completely tightened. Ignore any extra sleeves towards the bottom of the head end which are used when converting to a full-size bed.
If your foot end has corresponding feet, attach the feet to the foot end loosely either with two 80mm M6 bolts or tighten by hand. This will vary according to your model. At the top of each foot you'll find the "R" for right and "L" for left, make sure to match them accordingly.
Using the hex wrench and the last four M6 bolts, attach the foot end to the rest of the crib.
Place the crib on its back, the headboard lying flat on the floor. Now, tighten the foot end's feet all the way.
Return the crib back to it's upright position and double check that all the bolts are completely tightened.
Periodically inspect your crib for missing, loose or broken parts and repair accordingly. Never use a crib if it has damaged or missing parts.