You mean print a debug message on screen or to output log? Easiest is to add the following line to your code to see if your functions even run:
GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Red, “debug msg”);
You can check also Rama’s debug guide for other types of debugging (including onscreen messages that display variable values etc.):
For multiplayer debugging this might be a no brainer for you, but I’ll still write it:
With a multiplayer game, it’s best to always test as multiplayer - ie, put number of players to two and also run a test with the dedicated server ticked. I’ve found that most of my stuff usually works on either server or client, and about 50% of my issues that I’ve encountered with Shootergame has been me not doing replication correctly or not understanding who runs which code.