PC to Mac

Boy am I a newbie. It’s taken me three hours just to research and get to this point. I have a PC at home and have had for 20yrs. I now have an iMac too. I want to be able to send a message using our wireless LAN to and from the machines. But after hours of searching I can only find Spark that might do this. Installed Spark and have no clue how to use. it. Again, searched for documents and no joy. Can someone please point me at clear - step by step - instrcutions to help me do this. Thanks.

If you are looking for a messenger just to chat between two machines in you LAN, then you should look for something else probably. Spark has to connect to a server to be able to chat with other clients, it is not a peer-to-peer chat solution. Of course, you can still use it. You can install a jabber server, e.g. Openfire (from this same site), configure 2 users in it and then use Spark on both machines to login to that server and chat. This means server has to be running for Spark to be able to connect.