I don't know if you have the same kind, but my pictures might help point you in the right direction...
One of the pictures shows the top view where you can barely see the + and - terminals. Another picture shows where the contacts touch to charge the battery. Finally on my charger, you have to kind of wiggle it to get it to start charging (I suppose to make sure the contacts are actually touching well enough to get conductivity) and I usually have to play with the two buttons to get it into the right mode. Mine didn't come with a manual so I don't know what they actually do.
On mine, when it is actually charging, the green light flashes. It stops flashing when it's done charging.