If it was running until shut off I would guess look to the new battery.... does it have life? I know that's obvious but gotta ask lol. If it is charged perhaps the main ignition fuse got popped when installing the battery? Or, (and I know this sounds silly) you got the posts hooked up backwards? It's usually something simple, which can be hard to figure out because the simple things tend to get overlooked.
Battery has been getting weak in my 2013 Ford, went to town yesterday to get some alfalfa cubes for the horses so figured I pull into Ford's quick lube bay for an oil change. Shut the truck off and then it wouldn't start. What a perfect place for that to happen! Turns out the battery had a bad cell and they had me up and running in no time.