The list is a bit long. See below all we need. For the resistors and capacitors I've sued basically only 0402 size and that's a bit dificult to solder by hand. use a lot of fux. But first download the GERBERs and order the PCB to JLCPCB. You will also need the 3D case for the final multimeter. Get the OLED display, the amplifier ICs and the ADC. For the ATmega328 IC you could just desolder one from an old Arduino NANO. You will also need the LiPo battery and probably a boost converter to get 5V.