Use components to build interfaces. Search the component's name in the Component panel (Shift + A) or use quick search (Ctrl + E). Once you added a Component to your page unlink it to make changes. Right-click on the symbol’s label and choose unlink from symbol. This is the rule. We use overrides only as an exception for simple components that you'd rather want to re-style on the specific page within Style Guide (buttons, toggles etc. - mostly atoms).
Collapse is used to group similar content and hide or show it depending on user needs or preferences. It gives users more granular control over the interface and help digest content in stages, rather than all at once.