How to use dates in C?

I wanted to know how to implement the time.h library

The application must identify the client, the start and end date of the rental, and price paid for the rental and the payment date.

We have the following structures:

typedef struct Aluguer

    struct tm data_inicio;                  
    struct tm data_fim;                     
    int preco;                         
    struct tm data_pagamento;               
    int pagaEfetuado; // -- 0 -> não pago || 1 -> pago
}ALUGUER;



typedef struct Elem{

  ALUGUER node;

  struct Elem *seguinte;

}ELEMENTO;

The exercise asks us to list all vehicles available for rent for a certain period (date range).

How should I proceed?