Plug and play for 4 wheel drive

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Drop new motor in because the guy he paid to rebuild it ended up not having a clue what he was doing and took the heads apart left everything in the rain and weather for several months and broke almost everything taking out apart and by the time i got to it because he didn't think a female was able parts were missing posh pins rocker arms and that's just 2% of what he had going on so i dropped a new motor in he had the old one dangling over the truck on the picker i didn't see how to he unplugged the 4wheel drive and i am not familiar with anything 4 wheel drive i need to know what I'm missing i push the button on the dash and i can hear it clicking under the driver side and its not going into 4 wheel drive i think it's a plug and play if so i need to know where that it's located if it's something else other then a plug and play do Yu know what I'm over looking i refuse to get whipped by lack of knowledge i was hoping to pick some chevy masterminds, he pays good and the truck runs better then ever but i would like to finish it all so i get the other two jobs he has available single mom and Christmas and all i know he'll give them to me but i want him to be eager to give me all available work please help guys. ...thank you