Could be many things, but battery is probably the one, starter could be the other one, but from the screen message is probably your battery, mustangs batteries and known for being bad lol
I feel like someone that doesnt know how to do an oil change could mess up and put a different oil in their car, this goes the same way, you could end up eating through tires if is not done right, like i said you could learn and do it yourself or take it to a professional with good reviews and...
I mean, im a boosted v6 and even with the turbo kit im well under the price of the GT that i wanted, and the fact that i can gap every other GT its just funny