You can create your own external button connected to your camera to trigger stream/graphics with this rocker switch button:
Name of component: R13-112L-02-BBCR-L1
Important is that the button needs to have 2 separate wires for the button (camera input) and 2 separate wires for LED diode (camera output)
See the scheme below for four pins connector (the same wiring is valid for six-pin connector).
1 - 0VDC(-)
2 - DC output, 12 V DC Maxload=50mA
3 - Digital input, connect to pin 1 to activate ,or leave floating(unconnected) to deactivate
4 - Digital output
Check the video here
The button can be implemented in any box available in the shop with electrical components.
Settings in CamStreamer App
a) for triggering via button select as Triggering option I/O port (Input 1), for YouTube and Facebook select Manual version of the event, for other services select Stream type - Manual
b) for an indication of live streaming via LED select in advanced option Output 1 (led blinks during preparing and light once broadcasting is successfully started)
Settings in CamOverlay App
For triggering via the button in CamOverlay App select in Triggering I/O Port (Input 1)