Insert the 40 pin header into the PCB with the short pins extending from the component side, through the PCB so that the plastic base sits on top of the component side of the PCB with its longer pins pointing up above the component side. It does not matter which way round this is inserted. Solder the short pins to the PCB. | Insert the 40 pin header into the PCB with the short pins extending from the component side, through the PCB so that the plastic base sits on top of the component side of the PCB with its longer pins pointing up above the component side. It does not matter which way round this is inserted. Solder the short pins to the PCB. |