ImmoMapper is a search engine and doesn't have its own listings. So you can't list a home on ImmoMapper directly.
Here's what you could do instead:
If you are looking for a renter I highly recommend using Naloo's Immomailing to list the home for free especially if it is in or around Zurich.
Your listing should be picked up by ImmoMapper typically within a few hours although sometimes it might take a day or two.