Hamachi is a little bit of a weird program.
You need to "turn it on" first, to connect it to the internet. Then, you have to join a network; I don't have the new version, so it will look different, but there should be a "network" menu on the newer version. Enter the network name and password, and you'll join that network.
After that, you will need to find the person you want to play with (they need to be on a network you are also on) and their IP address, which will be the long number next to their name (193.42.5.62 or whatever it is). That will be important when you actually go to play them in Redshark/Apprentice.
From there, your opponent will be able to guide you a little better. But that's the basic stuff you need. ^^