If you just got a new battery, you need to charge it.
Yes, it's at 90%. If you don't charge it, that 90% is pretty much all you'll ever get. Plus, you might need to do this again someday.
Kevin, you have a battery, and a wire coming out of it that has four terminals, correct? Two of those will be the positive and negative terminals you're looking for. To charge it, as we know, you just need to connect the positive charger lead to the positive battery terminal, and the negative to the negative.
To find out which is which, use an analog volt meter (and see which way the needle swings). If you don' have one, you can also use a small DC electric motor - plug it in to the terminals coming off the battery until it spins up, and record the direction in which it spins. Then, figure out which leads off the charger make the motor spin in the same direction, and wire them one to one.
Once you figure out which terminals you need to connect to which leads, mark them.