How to implement a combo system with timing ?

Hi everyone !
I would like to implement a combo system with timing (like devil may cry games).
A,A,A = Combo 1
A,……A,A = Combo 2
A,A……,A = Combo 3
I’m using just one input for attacking (touch A), and I don’t know how to do this (I tried many things but it didn’t work).

This is the current system, without any timing:

https://image.noelshack.com/minis/2020/20/5/1589534099-animationmontagesnotifiers.png
https://image.noelshack.com/minis/2020/20/5/1589534095-blueprintsystem1.png
https://image.noelshack.com/minis/2020/20/5/1589534086-blueprintsystem2.png
https://image.noelshack.com/minis/2020/20/5/1589534105-combo.png

Thank you in advance for your answers [FONT=Segoe UI Emoji]

This is an early version of the game

To make a combo system you have to implement an “input buffer” where you keep a list of latest buttons pressed.

Thanks, I’ll try it !