2000 Oldsmobile Silhouette Just Put Transmison Now Will Start Even Turn Over By

Just put a transmison in my 2000 oldsmobile and now it will not start, it dont even turn over by the switch. It was starting fine befor I put the tran. in it. I dont know what the problem is.I also had to put new spark plugs and wires on my van,also a new motor mount and fuel filter.I dont know if I knocked something out of place when working on it or not.I have alot of money in this van for I have done other repairs in the past.I pray you can help me I am at a loss.Thank You so very much!!!!!!