Yes, the WifiManager will start in AP mode then you can configure the wireless network to connect too..
You can skip that if you know in advance the ssid and password..
// network SSID (network name). and network password.
char ssid[] = "YourSSID";
char pass[] = "YourPassword";
WiFi.mode(WIFI_STA); // Connect to Wifi network.
WiFi.begin(ssid, pass);
~q