Learn Bootstrap... need help with Lesson 7 in utilities and components

Hi! brand new here, i hope i am doing this right!

if not, kindly help me out!

i was told to go the JavaScript forum on this

my question

https://www.codecademy.com/courses/learn-bootstrap/lessons/learn-bootstrap-utilities-components/exercises/collapse?action=resume_content_item

i need help clarifying instruction 1 and 2

i am simply not getting the concept

please explain… and dumb it down a l little so i get it!