How do I set up call forwarding on the "speed dial" button on the Grandstream GXP2160?

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I have a Grandstream GXP2135, on it, with an incoming call, I press the "Forwarding" button, then I press the "speed dial" button on which the employee's number is entered, and the call immediately goes to him.
How to do also on Grandstream GXP2160?
In the GXP2160, when there is an incoming call, I press the "Forward" button, then I press the "speed dial" button on which the employee's number is entered, the phone starts dialing it on the second line, as if I did not press the "Forward" button.
Moreover, if after pressing the "Forwarding" button manually enter the subscriber's number, then "Send" (or Send), both devices behave correctly, namely, they transfer the call to the dialed number