Hey my name is Robbie I'm new here saw that alot of questions were being answered and i need some help

just got a honda a couple weeks ago and there was already a aftermarket stereo in it but the car ( 1991 Honda civic) only has the two door speakrs. So I pulled the deck out (pioneer) and I saw a bunch of cords not hooked up so I just weird speaker wire to the first cords witch were green and ran the cord to the truck and set up a sub back there just so I had some thing ( I dont have an amp ) and then I was driving and I noticed my dash lights to my speedometer, gas gauge, heating gauge, but my lights for my park,drive. Ect are working I dont know what the problem is I'm gonna look at my fuses after this I fairly new to this stuff please help