Mustang 2011 pats system

My car won't start, basically what I did is my remote and
key are together they're one. So the remote wasn't
working I go and buy a battery for the remote, it wasn't
the battery that was the issue. SO I decided to take it
apart the remote on the key, and there was no damage..
although the remote wasn't working the key would still
turn on the car. Me thinking I could program the remote
with the car with the 8 switch on and off solution would
program my remote back to working condition, in
conclusion turns out the key stopped working right after
that.. I don't know if programmed my car to forget my key
or what the hell. Checked battery and fuses still got
nothing, the car will light up the cluster but when I turn the
car fully n I just get the blinking red pats, driving me crazy
I haven't checked the fuses under dash. I don't know if I
need a new key or to get it reprogrammed or to what..
keep in mind this is my only key