Welcome to JUST ANSWER small engines, let me try to help you !!
The small line with the strainer on it is the suction from the tank, and goes into the top of the carburetor, the bottom line on carburetor goes to the fuel primer, and the big hose goes from primer back to the tank. It just has to be in tank, The primer PULLS fuel through the carburetor and aloows the air to go back into the tank.
Let me know if this does not explain it. Thank you.