in car lighting installation

[ap07civic]

i got my car as a present, so it doesnt have all the accessories i wouldve liked, and since the blue glow under the driver and passenger side costs like $150+, i decided i'd do it myself, cant be that hard, BUT


(noob)
i'm having trouble hooking up the red/black wires to the fuse box, and i wanted to konw if someone knew the right technique...i followed the instructions on the light but i cant seem to put the wires in the empty fuse outlet.. anyone got any ideas/? am i missing something ?