Idea 1 : for a combo
if animation idle is playing
+ Press A : play animation punch1
if animation punch1 is playing
+ Press A : play animation punch 2
animation punch1 OR animation punch2 is over : play animation idle
?
-------- Or ----------- Idea 2, for alternative attacks (your description sound more like that)
Set variable : punch_step basically to 1
if punch_step == 1
+ Press A : play animation punch1 + set punch_step to 2
if punch_step == 2
+ Press A : play animation punch 2 + set punch_step to 1
animation punch1 OR animation punch2 is over : play animation idle
?