My sister was in an auto accident and has been moved to an assisted living facility. The phone from her home has been moved there. It is an older model and we are unable to fine the owner manual. The VTech company no longer has it. We do not know how to set up the answering machine feature so no one can call her and leave a message. The phone is a 5.8GHz Vtech I5858 cordless phone. Can you help us?