Here is your panel.

Enjoy it while you can, because you will start by breaking it apart along the scored lines.

Odoo text and image block
Odoo image and text block

There.

Now you broke it.
 

Make some headers.

Snap off two sections of the .1" single row header pins so you have 17 pins on each.  Push the long end of the pins into the socket headers. The remaining can be used for the 6 pin SWD programming header if using an ST-Link or JTAG programmer.

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Add the digital board power header.

Snap off a 10-pin chunk of the dual-row .1" headers, and solder it in place. The board layout can only accommodate an unshrouded header, but red stripe is down, and the power circuit is reverse protected. You can also add the 6 pin programming header here if you want to use a programmer instead of flashing firmware over USB.

Odoo text and image block
Odoo image and text block

Stack the two boards and solder the headers.

The socket header should go into the smaller digital board.  Add light pressure so that the headers are flush with the PCB as you begin to solder.  Solder the pins on the two opposite corners of the rows and check that the headers are still aligned correctly. After soldering the rest of the pins, separate the two boards. 
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Add the digital board expander header.

This belongs on the underside of the digital board.  It's a right-angle header and may take a bit of balancing or propping to get it aligned to solder.  We use a little jig we made out of an old board. You can also put the expander cable on the header when soldering it in place to ensure the proper clearance. 

Insert the pots and LEDs into the analog board.

Be sure to snap any anti-rotation tabs off the pots, as those will prevent the assembly from sitting flush. 

Make special note of the 50k pot, RV2, PHOTO IS WRONG.

For the white LEDs (4 clear), make sure the short lead goes through the square hole.  Do the same with the bicolor (diffuse 2-lead LED).

Odoo text and image block
Odoo image and text block

Add the RGB LED.

The photograph shows the correct orientation.  The long lead goes through the pad with the heavy ground trace connected to it, which is also directly adjacent to the square pad.

Add the six jacks.

The next step requires attaching the faceplate, so we suggest inserting the jacks while holding the board level with the other hand.

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Odoo image and text block

Temporarily attach the faceplate.

Attach the faceplate and screw on enough jack and potentiometer nuts to keep it flush while soldering. Take care not to dislodge any components from the analog board. Push the white and bicolor LEDs through the faceplate holes, but keep the RGB LED flush with the PCB.   

Solder everything. Now you can flip the board over and solder down all the pots, jacks, and LEDs.

Propping the jack end of the board on something roughly the height of the knobs makes the assembly more stable.  Trim the ends of the LEDs off with a flush cutter.  It's a good idea to solder the lugs on the potentiometers as well (unless you put the 50k pot in wrong, in which case they are very difficult to desolder)
Odoo text and image block
Odoo image and text block

Solder the expander header.

If you're using the expander, of course.  Break away a 12-pin chunk of .1" dual-row pin headers, place, and solder as shown.

Place the expander potentiometers.

 Make sure the center potentiometer is 50k.

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Odoo image and text block

Place the expander jacks and pushbutton.

Pay attention to the orientation of the push button, there is a silkscreen indication of how the flatted side should be oriented.  Prepare to attach the expander to the faceplate.

Secure the faceplate and solder.

You will want to ensure that the circuit PCBs are coplanar with the faceplate for proper alignment of the button. It can help to tighten up the bottom jack and and top knob nuts at opposite corners of both boards. Make sure that the base of the switch is pressed up against the PCB when soldering.  It will fall down against the faceplate otherwise 

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Odoo image and text block

Reattach the analog board to the faceplate and insert the long header.

Insert the long 8 pin header through the analog board so that it is resting lightly in the socket header on the front panel. Attach the digital board to the analog board, seating the long pin headers before fully inserting. Keeping the base of the long pin header flush with the digital board, solder the two opposite pins on the header. Double check the alignment, then solder the rest. When disassembled, the long header stays attached to the digital board.  

No Expander?

If you're not using the expander, make sure you place the 3 jumpers as shown here.

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Odoo image and text block

Expander!

Insert your expander cable paying attention to the white stripes present on the board and the white wires on the cable.  You're done with the hardware build!

Now, its time to program the microcontroller and calibrate the unit.