Ok heres a updated schematics of the build: U need: some thin cable. 10 k ohm ptentiometer 400 ohm resistor transistor BD237 3-pin screw connector circuit board (i dont know what it is in english, but u see what I mean when u look at pictures.) heat plate (size dosent really matter) lets begin: first u need to do is screw the heat plate on the back of the transistor ( back side is where u see no text, front side is the side letters and numbers in it.) solder the transistor with heat plate into ur board. make sure the text side of it faces infront of u as u can see from the schematics and in the picture. (u can use glue to keep the plate firmly on the board). solder rest of the parts in (no matter wich way u solder the potentiometer and resistor). Now as u see there's lines with different colors in the schematic, consider these lines as cords or cables that u need to connect. Solder the red line (cord) from potentiometernleft pin to transistor's middle pin. solder transistor's middle pin to the first pin of the connector. next solder blue line (cord) from potentiometer middle pin to resistor first pin. connect resistor second pin to transistor right pin. solder green line (cord) from transistor left pin to connector middle pin. solder potentiometer right pin to connector third pin and thats it!! u have a (hopefully) working fan controller. If not then make sure u have connected the cords to the right pins and that u have the transistor soldered the right way (text should be infront). All u have to do from there is connect PSU yellow cord to the 3-pin connector's first pin (do not solder just screw the cord in). Next connect the casefan(s) (u can add as many fans as u like) red + cord to the connectors middle pin. Lastly connect PSU's black (0V) and casefan(s) black (0V) chords to connector's last pin. Make sure the controller is properly protected, so that it dont short circuit. U can put it inside plastic bag, just leave the bag open. Open computer and voila! now u can controll all ur casefans, with ur potentiometer!!! here's the way it looks like I recommend to add the cooling plate on the transistor to keep it from frying.