To record and assign voicemail greeting prompts for the menu that people will hear when they call the main number, first login to the admin panel.
Navigate to Phone System > Auto-Receptionist > Prompts Library, then click Record Prompts.
Type a name for the new prompt and then choose how to record it; a phone call or your computer's microphone. Record the greeting.
Once the greeting is recorded, you can listen to it. To complete this process, click the upload icon.
It will save the recording to the prompts library. Click Done.
Now that the recording has been saved, the next step is to assign it to a menu item. Go to Auto-Receptionist > IVR Menus. Select the menu to change.
Click Prompt and then click the Select button.
Click the prompt to be used for this menu selection and then press the Select button.
Click the Save button.