The agenda doesn't work, all my interactions are at the top of the day

The display you get is normal.

The interactions whose "Task" box is checked appear at the top of the agenda. Tasks are interactions that you perform at any time of the day.

Interactions whose "Task" box is not checked appear in the calendar at the start date and time of the interaction. These are "Rendez-vous" interactions.

To make the interactions appear at the right time in the calendar, uncheck the "Task" box for each interaction concerned (see screenshot below).