My fist step is to layout the box exactly as I want it to go together. I then label each corner with the same letter (below the scribe line) 

These are the tools I use for layout. 

Marking gauge - to mark the baselines
Marking knife and pencil
Dovetail marker (a sliding bevel works too)
Dividers
A small ruler (to set the dividers)
A small square (not shown)    

First I set my marking gauge to the thickness of the boards. All of my boards are the same thickness. I then make a light mark around all 4 edges of the long boards. Those will the the tail boards. On the shorter boards, I only mark the faces; not the edges 

Now I put both tail boards in the vise to lay them out. I like to do this for 2 reasons. It shows me the boards are square and parallel to each other (important come assembly time), and it saves a bit if time on the layout

I start with marking 1/4" from the edge for the half pins on each side

Then I use dividers to lay out the rest of my spacing. I want 6 pins, so I adjust the dividers slightly until I can walk them across the board 6 times. Megan Fitzpatrick from Popular Woodworking has a much better way to do this

Once the holes are marked I measure 1/8" on each side for the 1/4" pins. I'm going for strength, not show here.

I use my dovetail marker to finish up. I use a knife on the top, and a pencil on the face. It's very important the cuts are plumb and straight. The exact angle isn't important at this step, so I don't want a knife line. I find it easier to just go with it if my angle is slightly off rather than try to correct it 

Then I saw them out

Once sawn, I like to remove the waste. I get close to, but stay off my baselines.  

Now they are ready for chiseling

I like to remove the half pins first. I do this by sawing them

I reinforce the light gauge line with a knife against a square

Then I remove a V with a large chisel

Now I have a built in saw guide

I carefully saw down to my baseline and pop off the waste. If needed I'll clean up with a chisel

Time to remove the waste. I'll be using chisels of various width, a square, and a knife. I also keep a strop handy as I like my chisels razor sharp for the whole operation. In addition, pine dents really easily. I keep a brush handy and sweep off the chips before flipping the piece over

Before chiseling, I need a deeper baseline. I went light with the gauge since I will be planing it off. I drop the knife into a gauge line then bring up the square. I then make a deep knife cut into the waste only. 

After that is done I secure the piece to my bench hook with a holdfast. 

When chiseling out the waste, I start far back from the baseline and go all the way down into my bench hook. I slowly work my way back. when I get to the baseline. I chisel about halfway down

Here is the piece flipped over. Now I repeat the same process 

Clean tail board

I then put it back in the vise and make sure the floor is level and square. I also use a pocket knife to clean out the inside corners 

To transfer the tails to the pins, I used some scraps the same height as my vise. I normally use a dovetail alignment board, but these pieces are too wide

I then line up the baseline of the tail board with the pin board in the vise. I use a knife to transfer the marks being very careful not to shift the piece

Here are the pins laid out

Now I draw the vertical lines down the face using my dovetail marker

And carefully saw the pins. Unlike the tails, wandering from these lines is no good. Take your time here and stay inside. I'm a firm believer in "sawn not carved" so I aim to split my line. I don't pare the joints with a chisel after. 

Like with the tails, I remove the bulk of the waste with my turning saw. 

I like to test fit the joints at this stage. Perfect fit off the saw. Now If I am careful cleaning up the waste, I'll have a good fitting joint. 

I like to chisel all the way down from one side when cleaning up the pins. Rather than chisel half way then flip the board. I requires a lot of care and attention with the chisel, but I I prefer this process. 

Done with the dovetails

Before gluing it up, I finish the inside.First I plane it smooth with my smoothing plane, then I'll use whatever finish is appropriate. I'd advise against finishing the inside of a tool chest, but this is a rather small one. I didn't apply finish at this stage because I hadn't worked out the design for the trays yet

I'll be using a square, a mallet and some hide glue. If you haven't used hide glue yet, this is your chance. PVA glues tend to expand the wood a bit and create artificial tightness in the joint. The opposite is true of hide glue. I cut my dovetails on the tight side, and hide glue acts as a lubricant.  Also it has a very long open time so you have a while to assemble.

I lay out the box according to the lettering I did a few steps above

And apply glue to two of the corresponding pin boards 

I then tap the tail board home

Once done I flip the assembly and apply glue to the pin boards again 

Then I tap the last tail board in place 

I then check to make sure the inside and outside are square. If they are good, like here, I don't feel the need to use clamps. The joints fit very tightly and do not come loose. I'll let it sit overnight before proceeding. 

After a little clean up, I have nice looking and nice fitting joints 

Like with the previous steps, now is a good time to clean up the shop. I also like to resharpen any planes or chisels I've used this far so they are ready for the next operation