Many of these batteries ship without acid so you need to add acid to the battery to the proper level and not water. Battery instructions often recommend that you do this over a period of time as the level you fill to can go down after the battery sits for a few hours. Assuming that is the case, my trickle charger and others won't even charge a new battery because it has some built in safety device or related BS that kicks in and won't charge the battery if the voltage is too low. I've had success filling the battery and then going on several 20-30 minute rides to charge the battery.
Or perhaps you can take your battery to a battery's plus and they might be willing to charge it for you overnight. They usually prefer that you buy the item there.
Beyond that, make sure all the wiring under the seat is properly connected and check the rectifier for connectivity as well. Double check the wiring from the stator connections which will be coming out of the frame near the carburetor. (edited)