As soon as you are connected to steam, just execute the nodes. There is no “connect to steam now” node. You need to call SteamApi_Init() from C++, but unreal does that already and my C++ code does that once the first time one of the nodes is called. If any of the nodes fail because of initialization issue, then because something went wrong when SteamApi_Init() was called from C++. But you can’t do much about that. Just start steam, do the config and you are good to go.
Edit: I provided the node **IsSteamInitialized **for checking.