Engine Fault Service Now?

I have the vehicle listed above S, that I installed a new battery in January. The owners manual mentions the battery monitor system but doesn't mention that it needed to be reset. How difficult is it to change a battery even for a girl right? Wrong! Two weeks after I changed my battery my alternator went out. I didn't think anything of it, just had it replaced. I then started to get random messages on the display screen for option faults that weren't even options on my car such as.
Hill Start Assist Not Available and Steering Assist Fault Service Required. Also Steering Loss Stop Safely and Transmission Not in Park when I was driving. I also had to have my key fob replaced because I had the message No key detected. My new battery is toast due to being overcharged because the battery monitor system wasn't reset and to top it all off my car is completely dead with the messages Engine Fault Service Now. All this just because I installed a new battery. I have replaced the battery, the cable with the sensor and the connector as soon as the key is turned on the my Key programing starts then the Engine Fault Service Now message shows. The car does nothing. What could the engine fault be and how do I fix it?