I checked instructables and ran an Internet image search for plans and ideas. I decided to use ProRock's "Pallet Trunk"(https://www.instructables.com/id/Pallet-Trunk/) as the base design for the box.
As for the lid, it looks like the one from NutandBolt's "Simple Storage Box" (https://www.instructables.com/id/Simple-Storage-Box/), which I must have seen during my browsing and subconsciously committed to memory for future inspiration.
I tried to remember to take pictures as I went, but I didn't do a great job. If you get stuck, check out the instructables I just mentioned and they should help you out.
Step 1: Preparation
As I stated previously, I had salvaged a bunkbed. Actually, I only took the frames that the matresses lay on. Breaking these down left me with 4 long pieces of 1"x4", a number of shorter 1"x4"s (maybe 16?), and a few handfuls of bent, broken, and otherwise useless staples. I figure that the average instructibles viewer knows what a 1"x4" looks like, so no pictures.
A piece of plywood that will fit as a floor for the box is also a good idea, but I didn't think of it 'til I got to that point.
I have a coffee can full of reclaimed screws. From it, I was actually able to pull ~90 1-1/2" wood screws. If a magic coffee can of wood fasteners is not available, I would suggest buying enough screws. I used a few longer screws where they wouldn't come through the wood and I did switch to nails (from my other magic coffee can) when I ran out of the right sized screws.
Hinges (if you want a hinged lid).
Your choice, of course, but I used a water-based polyurethane (left over from a previous project.
(Not all are necessary, but I used all of them)
measuring tape and pencil
table saw with cross-cut sled
2 cordless drills (one for drilling holes and the other for driving screws)
a Picquic multi-bit screwdriver (one of my most favourite tools ever)
drill bit (slightly smaller diameter than the screws)
coarse-grit sandpaper (80 or 100 grit) with block
fine sand paper (I actually tried out a sanding sponge, 300-grit)
radio (for talk or tunes while working)
Step 2: The Sides
Using my table saw, I ripped the 4 long pieces in half and cut them into 4 30" lengths and 4 22" lengths. Using two of each length, I arranged them into two rectangles (that I call hoops because it's like making a rectangular barrel). I used reclaimed screws to fasten the hoops.
Then I assembled the walls:
Using my cross-cut sled on the table saw, I cut a bunch of 1"x4" to my desired length (16" in this case). I ended up needing 28 of these: 9 for both front and back and 5 for each side.
Laying one long side of each hoop on my work-space (the floor), I used the remainder of my reclaimed screws to fasten the top and bottom ends of my wall pieces to the inside of the hoops. I wanted as few fasteners showing as possible so I screwed them in from the inside of the box. Here's where two drills comes in handy: one to pre-drill the holes to prevent splitting (careful not to go all the way through) and the other to drive the screws.
As you can see, I ended up ripping a couple of sections to make them fit and still look decent. I also had to do the same for the box ends.
I should say now that I smoothed all pieces before assembly. I rounded exposed edges with the block plane. Used a chisel and a carving knife to cut out and smooth splinter-points (usually ragged staple holes) where I felt small fingers stood a good chance of getting slivers if they happened to brush the area. Then sanded, first with a coarse grit (I had 100 grit available to me) then finer grits (220 then 300) for that smooth and silky feel.
Step 3: The Bottom
I actually had not planned what to use for the bottom, but I found a bit of plywood (might have been 1/4" thick) that only needed a shave at one end to perfectly fit my box. Lucky!
I screwed the floor supports into the sides. Then I slipped the plywood floor down inside and put a few nails in to hold it in place. A couple of nails stuck out the bottom, so I bent them over and filed the exposed side a bit so as not to scratch any floors.
Step 4: The Lid
I bought hinges (the only thing purchased specifically for this project) and put them on the back of the box, connecting the lid. I debated trying my hand at making my own hinges, but I eventually backed out (wisely, I think). I outlined them on the box and took them off again. I then cut recesses to fit the hinges using a chisel. Reattached hinges and the box was ready for finishing.
OK, not quite. I wanted a handle for the lid that would not be uncomfortable while sitting on it. I decided to drill a couple of holes in the front plank and then, after applying finish, push a piece of rope through.
Step 5: Finishing
For application and drying, I set the box on top of a couple of pyrex-type cassarole dishes I had salvaged so that the finish wouldn't stick to it . Once dry, I pushed the rope through the holes and tied the ends underneath the lid. My wife thinks the rope is ugly and wants me to use something else. I keep my eye open for a nicer piece of rope.
Behold the unique beauty of reclaimed lumber!