How do you find torque

You have just bought a used car engine from your local scrap dealer and are thinking of borrowing your neighbor's wheelbarrow to move it into his garage, which you have already borrowed to fix your car. The engine weighs 137 kg and you estimate, from the geometry of the wheelbarrow and of the engine, that the center of mass of the engine will be about 45.0 cm from the center of the wheel of the wheelbarrow.
a. What will be the magnitude of the torque, in N-m, of the engine about the center of the wheel?
b. Assuming that the wheelbarrow itself has negligible weight, what will be the total force you must apply on the two handles, in N, if the handles are 168 cm from the center of the wheel?

Can someone show me how to answer these questions?

I call torque a moment, just another word for it.

moment (Nm) = force (N) x distance (m)
force (N) = mass (kg) x acceleration (ms^-2) OR derived to weight = mass x g (gravitational field strength)

Now you answer your question based of what you take g to be, I don't have a calculator with me so I'll say it is 10 ms^-2 but your teacher may want you to use 9.81.

a. Force = 137 x 10 = 1370 N
45 cm = 0.45 m
moment = 0.45 x 1370 = 616.5 Nm

b. 168 cm = 1.68 m
Rearranged: Force = moment / distance = 616.5 / 1.68 = 367 (3 s.f)

Check with a calculator if they are right since that'll help you understand (and because I did these in my head pretty quickly).