PCB is reversible; use one for the left hand side and the other for the right.
### Diodes
__For non Low Profile keyswitches__
Solder diodes as indicated in the picture. You can place it on either side, but front side is recommended if you implement under-glow LED. You can use SMD diodes too.
If you use low profile keyswitches, you have to implement SMD diodes __on the back side__.
Otherwise, diodes will interfere with top plate.
### LEDs (Optional)
Implement LEDs under keyswitches (No. 7 through 27) upward facing, and others (No. 1 through 6) on the back side(under-glow), as indicated in the picture.
For No. 1 to 6 LEDs, solder the pattern on the side of the device (highlighted in pink on the picture) and the PCB pattern(blue on the picture). Apply flux and take small amount of solder with a soldering iron and press it on the edge of the patterns.
LEDs are connected in the order of the number on the picture above. If it turns on only halfway, it is likely that first LED that doesn't turn on or the last LED that turns on is not implemented correctly.
### Jumpers for OLED modules (optional)
To use OLED modules, short circuit the jumper patterns.
Implement pin headers in the white frame, then install ProMicro with its backside up. (The picture is the right hand side, but it's the same for the left hand side - pins into the through holes in the white frame, backside up.)
Using the default keymap, OLED will show information on the keyswitches being pressed. Check the connections by short-circuiting key-switch soldering pads with tweezers. Check all of them.
If you have mounted LEDs, also make sure all of them are turned on.
To turn the LEDs on, you have to edit the `rules.mk` file. If you use the default layout, it can be found here `keyboards/crkbd/keymaps/default/rules.mk`. Add the following line to the top of the file:
```
RGBLIGHT_ENABLED = yes
```
Compile and flash to both sides and all LEDs should turn on and __glow red__ if you have soldered everything correctly. If you run the default firmware and the LEDs turn a differrent color, the data to the LEDs is probably corrupted somewhere along the way. Check the LED before the first one turning a different color using the troubleshooting guide below.