Question

[Username123]

What is a and k supposed to be?

 

[peccary]

Anode and cathode.

Edit: this should be helpful: https://forum.pedalpcb.com/threads/led-polarity.5/

 

[Username123]

Ok thanks. Is this the spot for the LED?

 

[Robert]

Ok thanks. Is this the spot for the LED?

Yep.

 

[EGRENIER]

The way I do my led is to insert the led in the hole but no solder them in place. Insert your board in and fix your pot nuts, then pull the led with plyer until the led fit in your led bezel. Push lightly with a chop stick to be sure the led is well in, solder in place and clip. After that the led will land at the right place every time.