line out converters?

[burnoutking999]

I am installing a line out converter and have two wires to each speaker... they are both hot. Apparently its a common ground system and has a hi and mid rear setup with the hot wires going in.

ok, i have the hots tapped into. For the grounds what do i do? just chassis ground? do i have to run wires from the radio grounds or is any ok? im not clear on this.

basically the amp is wired and the power is good. the sub and box to amp is wired. the only thing left is this stupid line out converter! any help is greatly appreciated.

[burnoutking999]

premium sound
left rear speaker door bn/pk and og/rd- super cab
left rear speaker tn/ye and gy/lb- others
right rear speaker bn/pk and or/rd- others
right rear door speaker bn/pk and or/rd- super cab

the bolded are my speakers. i tested them on an old rx7 speaker(cries softly). what are the + and what are the -?

THEY BOTH READ HOT WITH A GROUNDED TEST LIGHT! I need this to finish. other than that im done! the speaker i have plays music either way(CONNECTED ANY WAY) DOES THIS MATTER?