Hey Osama,
Its been a year, no one has answered to this question. Anyways, my answers might help others.
Steps involves:
1. Download SOAP UI {Understand how to use it by watching few videos, there are various other Http Clients like Postman too. You can choose based on your comfort level.}
2. Create User Template before creating an User
3. Create User with the help User Template created in the above step
Creating User Template:
https://<Connection-ip>/vmrest/usertemplates?templateAlias=voicemailusertemplate
<UserTemplate>
<Alias>SapTemplate</Alias>
<DisplayName>Saptharsh Template</DisplayName>
</UserTemplate>
you will receive the user template object id. You can view this template by hitting a GET : https://<Connection-ip>/vmrest/usertemplates
Now create User
https://<Connection-ip>/vmrest/users?templateAlias=SapTemplate
<User>
<Alias>SapHegde</Alias>
<DtmfAccessId >123422</DtmfAccessId >
</User>
The response would User Object-Id, /vmrest/users/050dbd89-5bb8-4bd7-987f-e322c0c8c991
Now make a search in Cisco Unity Administration, Using "Alias" containing "SapHegde."
