Hit Zip, punch in your zipcode and hit enter. Let it scan until it gets to MOSWIN. Hold on that system. St. Louis Fire/EMS should be on shortly talking on one of the sites. Make sure you have the distance set to 25 miles or something like that. Enjoy listening to it that way. (This is not the best way to do it but at least you will be hearing them.)
Then watch a Youtube video on how to program with Sentinel so you can get the correct tower(s) programmed in to listen to St. Louis city Fire. It is not difficult but there are several steps you need to figure out first. There is a bit of a learning curve with these scanners.