Hi there, Otilia! Thanks for getting in touch and welcome to the forums. 🙂
Currently there is no way to show only the first instance of a recurring event in Month View – though you can add your vote for this feature – but beyond that this would take some custom development work on your end.
One approach might be to adapt the calendar template (see our Themer’s Guide for details) and maintain a list of any recurring events that have already been rendered – then ignore future instances.
Sorry I’m unable to provide a concrete solution for you here, but I hope this helps answer your question.
Cheers!
Geoff