Hi @Maria_Ruisanchez,
welcome to Airtable Community ! :slightly_smiling_face:
You cannot add multiple time intervals in the same field, the field is for either a start date or an end date. You have to enter for each event a Start Date & Time and an end Date & Time so you can display it in the calendar.
If this helps, please mark it as a Solution so others can see it easily.
BR,
Mo