It is quite easy to build your own bed frame, and to get your mattress up off the floor from the dust and summer bugs. You can make it as fancy as you want with a carving tool, and carve figures or patterns in the wood afterward, or even paint and stain it to match your room's decor.
Step 1 - Bed Height
The first thing you want to figure out before assembling your bed frame is how high you want it off the ground. Your main bed posts simply have to be measured the correct distance from the bottom of the side rails. From the bottom of the side rails, after the supports and base are in place, your actual bed will sit 4 inches above the bottom of your side beams. So if you want your bed to have a 10-inch clearance off the floor, you would measure the bottom of the rails to be 6 inches from the floor on your corner posts. With platform bed frames you have more control over the height of your bed, so you can make it higher or lower depending on your needs. They can be easily adjusted later by simply moving where your rails are attached higher or lower on the bed posts.
Step 2 - Assembly
When you assemble your bed frame on the bed post with the hangers, first attach both the head and foot boards to the side posts at your desired height, and then secure those together on the corner posts with your side rails. You can add another beam at the top of your bed frame headboard or the foot board to make the ends more stable.
Step 3 - Adding Supports
Your bed frame is nearly complete, now just to make it so that it will hold your box spring and mattress. To do this simply take the support blocks and mount them even with the bottom of the side rails 1/3 of the way in on both ends, measuring in from the headboard and foot board. Secure them with the wood screws in a triangle pattern to add stability. These blocks are going to be holding the plywood base under your bed. Do not over secure the blocks; it will split and crack the wood making it unstable. Use 3 screws on each end of your 8-inch supports, in a triangle pattern.
Step 4 - Last Touches
Take the plywood sheet and lower it onto the supports you have added onto the bed frame. You are now ready to add color with paint or even carve on it with a carving tool, whatever you want. It is your bed frame and you can customize it and eventually learn to add drawers and the like, all under the same original frame you have just made. Once it is completed, put your box spring and mattress onto the plywood center. The bed should fit between the side rails, the foot and headboard with little effort.