Help

Hello I’m new to forum and getting my butt whipped
In inherited a 2000 e825 4 seater
When I got it there was no charger, ignition wires cut and no batteries
So far I have new batteries and a delta Q 72 v
Three wires coming out red, green and black white tied together
I followed the ignition wires and one went to circuit board ( good) and other to a unplugged plug that goes no where’s
Don’t know what to do to even start

Please advise is there any pics of a delta Q hooked up in one of these vehicles … Thank you