Here is a very helpful link..
http://straightrazorpalace.com/showthread.php?t=12239
It should get you started. I only have unused Iwasaki razor, haven't got Tosuke yet. Hence, no hands-on experience. I understand, however, that Japanese razors can be used with concave and convex sides against the face, although our in-house expert thebigspendur uses one side only. My bit of advice is to go slowly (wise thing to do with any straight razor anyway). Good luck and please let us know how it goes.
Dariusz