How to correctly render only one react component?

Question

React

The question is simple - there is a calendar (component a). When I click on the date, I get props that need to be processed in component b. How to organize switching from component a to b with the same click on the calendar? I used to switch components using router and link, but here the whole calendar component cannot seem to be a solid link. I would be grateful for an indication in which direction to dig)