[Dovecot] Out of office reminder with sieve

I found in the wiki the out of office reminder option. But the sample is looking for a .out-of-office file. I can not find out how to create this file. I use roundcube to set the out of office with sieve.

what is the best way to implement this.

Second question, where are the addresses stored that have send an e-mail to the user who has out of office set?

thanks regards, Johan Hendriks