Mk103rs nothing happens

Could anyone help me figure out what I did wrong?

Pay more attention to the manual and you will find out that led’s have a polarity! LD1 and LD3 are mounted reversely.

Thank you. How could you tell?

The leds have a flat side. That flat side of the led should be where on the pcb also the flat part of the led is drawn.

Outside of that your soldeing looks good.

Just my thoughts