Well....according to this...
https
/www.cnet.com/products/jbl-pro-power-bp1200-1-car-amplifier/specs/
you can use a total two ohm load or a total four ohm load (and I imagine anything in between).
If you wire the speakers in series, the impedance adds.
If you wire them in parallel the impedence = (R1*R2)/(R1+R2) where R1 is the impedance of one speaker and R2 is the impedance of the other.