Where API key for REST API is configured?

[Vodnik]

I'm doing first steps in using 3CX V18 REST API interface, but all requests results with 401 Unauthorized.
I expect that authorization should use API key, but can't find where it is configured in 3CX management.
Any advice for this?

 

[SweetAction]

it's at :5001/#/app/settings/webmeeting/1

(settings -> Conferencing Settings)