Looking for some tips regarding king (absolute beginner)

I got tekken 8 three days ago and am having a blast but this is my first fighting game and due to English not being my first language tutorials are a pain to understand

I main king as i love wrestling and i am having a blast but i just can’t figure out some things

The imputs for muscle armor do not seem to work, if anyone has a video showing me the input i would really appreciate it :) because i am definitely misunderstanding something

The main problem i have with king is that once someone corners me i am done for, are there any ways to counter this?

And i am just looking for the basics I have played 104 matches with a 23% win rate so i need some improvement. I do not really care about how much i win as i am having a blast ^{^}