[Vuejs]-Using bulma accordions, out of two accordions , how to display the later accordion , on click of a button inside the former accordion?

For Bulma + Vue, i would suggest Buefy with its Collapse with Accordion effect (doc link here). Basically you just need to use v-for loop for indexing, and trigger click event per button according index (e.g to open 2nd after click Btn1, make condition open to index 1 (starts from 0 in array), and open 0 and 1 indexes for Btn3 click)

Hope this helps.