If you want multiple users to be able to answer a call, then you add the users into a call / ring group.  Every member of that call / ring group will ring simultaneously on an incoming call.   The first to answer the call will receive it.

If you prefer, you can create more call groups and allow more complex routing such as if one phone or group of phones doesn’t answer then it calls a different set of phone etc.

Multiple call groups are also used really well when using an IVR menu so that different phones are rang depending on the option selected by the caller eg. Press 1 for sales rings only the Sales group.