Jump Start help!

[Max Mabazza]

hi everyone! thanks for helping me out with my last problem(fuel filter? i don't know!). im pretty sure it did the trick. i cleaned out the fuel filter and SO MUCH gunk came out. but i cant be sure yet because my battery died from all the times i tried starting it without cleaning out the filter!!! anyways, i have this portable jump starter that my dad bought me and i know where to clamp the red clamp, but i dont know where to clamp the black one. it says to clamp it onto the engine block but i have no idea what that means. can anyone help me out? heres a pic to give you guys a better picture!