first you must weaken the ghost mecha
second how to know if the ghost is weak?
the ghost mecha will have a red glow
third thats your que to use ghost trap weapon
is easy you know but note:that capture of the ghost depends
in the percentage capture of the trap

you buy a ghost mech so you have a higher chance to capture the mechs. I think all the
ghost mechs have 100% chance, im not sure though.