Calendary Prototyping

I would like to create a simple calendar view where selecting one date deselects the other previously selected. The calendar does not have a position without selected days, so it starts from the current day, and then you can go to the past (no future needed) and select a date, which deselects the one that was previously active. The date component has two states, default and active, there’s no hover, disabled, or multi-select. Not sure where to start, if it’s a conditional or a variable or something else. I’ve tried to watch some videos but they were focusing mostly on more complex things, but not this simple case. Thanks!

The only interesting video I found is this in which the behavior of the radio button is reproduced with variables and conditionals, which is very similar in terms of necessity. The path is clear, except that applying it to 31 days is certainly different than to 3 radio buttons. Any suggestions on how to optimize this process? Thank you.