You have one large fuel line and one smaller. This eliminates some chance for error. If you have 2 small fuel lines to the carburetor connect them and start the engine. Reversing the fuel lines will not prevent the engine from starting. If you have them connected backwards, the engine will start and die. Reverse them and you will be correct.
The routing of the fuel lines vary from model to model. Keep in mind that the primer bulb circulates fuel from the tank, through the carburetor, and back into the fuel tank. One line goes from the fuel tank to the carburetor. One line goes from the fuel tank to the primer bulb, from the primer bulb to the carburetor, and back to the fuel tank.
Normally the fuel intake goes on a small line in the fuel tank. I am sending you an image of the most common routing for chainsaws.