Which exact model Uniden DECT phone do you have? There are a number of models. Some require you to set up the answering machine from a handset. Other models have a Menu button on the base station, as well. The entire list of DECT phone manuals are here: http://www.uniden.com/scat/dectphones_mnl
. They are listed in alphabetical and numerical order. Ignore any digits after the dash in the model number, that indicates the number of handsets in the original package. My experience with Uniden DECT phones includes systems where the menu is accessed from the base like the D3588, http://www.uniden.com/content/ebiz/uniden/resources/ownersmanuals/D3588om.pdf .
The following directions work for the Uniden systems that I have used to set up the . First make sure that the answering system is on at the base station and the phone is in standby. Next press the Menu/Select button and use the Up/Down arrows to navigate to Answering Setup. Press Menu/Select to enter the submenu. Then navigate to the different options in this menu and press Menu/Select to enter them.
To record a greeting message, navigate to Record Greeting. Press Select and wait for the "Record Greeting" response. Speak your greeting clearly (between 2 and 30 seconds) and press Select to Stop the recording. You'll hear the greeting repeated. Press End (on the handset) or Stop/Cancel on the base to interrupt the playback.
Next press the Phone Book button to go back up to the Answer Setup menu. Select Greeting Options to switch greetings (if your model has a default greeting). Use Select to switch between greetings. (Arrow keys to swap; Select to confirm.) Use the Ring Time option to select how many rings before the unit picks up. If you wish to use the answering system when you are away, make sure to set up a Security code and press Select to confirm the code. Make a note of the code. Press End to exit the menu system.
Note: if you have Voicemail from your telephone provider, you will need to ensure that your Uniden phone picks up before the Voicemail service.
I hope this helps.