Grégoire,
I can help with this.
You are looking to put an event on different dates, but not the same hours, correct?
There is not method directly to do that, but you could use something like the Duplicate Post to “Clone” an Event then go in and edit the date and time for the other days.
Duplicate Post
That is what I usually recommend to do so you do not have to recreate all the information for each event.
Let me know if that works.
Thanks