Mom42boys

I had to put a new battery in my 2008 MDX and although it started fine right afterwards, I'm now having issues with the red light illuminating on both fobs and the vehicle not starting. I'm new to the anti-theft triggers on cars (my last vehicle was a '99 Olds Aurora) and I can't figure out what is wrong.
I can't afford to take it to a dealer or mechanic so I really need some ideas for whether or not this is anti-theft issues or other mechanical problems.
Help!
(I'm also new to forums so please be patient &#128522