When you click on Answering Rules, you will see the option to set the Ring for Seconds, found in the upper left side, below the Answering Rules bar. This is what controls how long a call attempts to ring you.

When you click on Answering Rules, you will see the option to set the Ring for Seconds, found in the upper left side, below the Answering Rules bar. This is what controls how long a call attempts to ring you.