Ligatures and alternatives letters - how to in CSS

Hi , the custom font that I'm using has alternative A, L, T, etc and has great ligature between letters.
I ask the font creator how to you it and he send me on this website :
https://sparanoid.com/lab/opentype-features/#flac

I tried to implemented the code that I found on the website in my CSS but it doesn't work.
Someone knows what I am doing wrong?

Picture : My code

Thanks 🙂
 

Can you share your site url? We can help easier

Hi there @tuanphan, I'm wondering the same thing, wonder if you can help out?

Site URL: https://www.abbieosmon.com/

Using font 'Madelon Script' I want to add code that specifies that the alternate capital 'A' character is used across the site. Is this possible?

Thank you,

Tom